LaverdaForum

Laverda Forum => Technical => Topic started by: Vince on May 18, 2016, 10:23

Title: Harsh Cer Forks.
Post by: Vince on May 18, 2016, 10:23
I have been chasing a harsh fork action for a long time, changing fork oil and emulator spring preloads with not the desired effect. I did a long search on the web about emulator tuning and have found some interesting stuff I am about to try. I found a few have tried this, I suspect that my really old emulators came with 1 only slow speed compression  bleed hole. Tomorrow I am going in for another look.Here is another take on this from another forum member.

i'm using .85kg r-t springs. preload is a little more than 30mm as i recall.
blue springs @ 3 turns on the emulator. two slow speed bleed holes in emulator

Its the small hits I am trying to tune out, the bike gets a bit vague
in long sweepers with a choppy surface.
Title: Re: Harsh Cer Forks.
Post by: Cosi on May 18, 2016, 11:08
Surely, and I mean no offence 85 springs are a little light on for you
Title: Re: Harsh Cer Forks.
Post by: Vince on May 18, 2016, 11:15
I have 0.95 springs,I recently heard thats the strongest available from Ibock,sp, and there staying. Its the 2 slow speed bleed holes in the emulator,in the plate under the spring in the emulator. Seems they can have 1 to 4 holes, I am hoping mine being a very early one came with 1 hole. 4 holes = softest slow speed damping and 1 = the firmest. Going to add another and see what its like.
Title: Re: Harsh Cer Forks.
Post by: Cosi on May 18, 2016, 11:29
Sorry mate i read you had .85  springs, I guess the next thing to ask is what's the arse riding on, how much oil and weight in the front , who set it up?
Title: Re: Harsh Cer Forks.
Post by: Vince on May 18, 2016, 11:42
I set it up, 15wt at 130mm fully compressed springs out, 3 turns on the emulators . Big hits are fine, its the braking bumps into bends,small square edged bumps. Its easy to return to 1 hole if it doesn't work.Bit of solder. These extra holes are popular with dirt bikes running emulators looking for plush suspension. Thats usually 3 and 4 holes.
Title: Re: Harsh Cer Forks.
Post by: Grant on May 18, 2016, 12:00
Have you tried lighter weight oil?
Might help the forks react better to small bumps.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 18, 2016, 12:24
Yep,tried 7.5 and 10. There holes are mentioned in the emulator info sheet when you buy them,seems they don't get much attention though. Lighter wt oil does flow through these holes easier and does speed  the fork reaction but it works against having the rebound I like. So I am hoping with 15wt and 2 holes it will do both.
Title: Re: Harsh Cer Forks.
Post by: breganzane on May 18, 2016, 12:54
If you're talking about bumps, then theoretically that is mainly high speed damping and thus handled by the emulator plate lifting off the seat to allow a decent amount of oil to flow.  This is controlled by the emulator spring weight (colour coded) and the preload on them.   I've used blue springs with 2 turns and found it to work ok as a starting point. 
Spring weights according to Racetech:
FPEV VS026   EMU VALVE SPRING 26 lb CHROME
FPEV VS040   EMU VALVE SPRING 40 lb BLUE
FPEV VS064   EMU VALVE SPRING 64 lb YELLOW
FPEV VS101   EMU VALVE SPRING 101 lb RED
The emulators often come with the yellow springs installed, which seem too stiff to me.  What springs in your emulators and how much preload?

Logically, if you want the high speed damping to kick in earlier, you want to back off the preload/weight on the emulator spring.  Be aware it's some stupid american bolt size and requires a 67/156ths allen key or some such.

The extra holes in the plate may also help, but those mainly control low speed damping such as that of brake dive, or gentle 'whoop-de-doos' in the road.

EDIT: You have 3 turns on the emulators but do not specify what springs.  Reduce to 1 or 1.5 turns for a noticeable effect and see how it goes, bearing in mind you might need to tighten them up a bit again if you lose composure in the more gnarly sections.  If you're running yellow spring then get a set of blue ones.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 18, 2016, 13:26
I think there blue springs, but the color is gone now.They have been there for at least 10 years. I have tried a few different preloads. Going to look at the holes tomorrow.
Title: Re: Harsh Cer Forks.
Post by: breganzane on May 18, 2016, 13:58
Will be interesting to hear how it changes things.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 19, 2016, 03:20
I did something dumb, I changed 2 things at once. I like a nice soft compliant suspension so while in there I backed off the emulator 1/2 a turn,wish I hadn't. I liked it better at 3 turns. As I had hoped the emulator did have 1 slow speed compression damping hole, 7/16 of an inch. O shit I forgot I only do Imperial drill bits,here comes Brett's I told you so, we have an Imperial Metric argument going. So I drilled another 7/16 hole 180 degrees away and took the bike for a spin around the block. Its definitely more compliant to small road irregularities, feels a lot more comfortable
on the small stuff, but a far bit worst with the spring preload backed off.Back in I go.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 20, 2016, 06:40
I am leaving the Cer forks on my 3C alone till after Sundays ride, be a fairer test. Today I did a lap of the Old Rd on my Pantah with 38mm Maz forks set up as I expect the same as the Cer in my 3C. Its been a good while since I rode it, a horrible 40c 600k runs last year that had the suspension beat me to a plup. Since then I fitted Emulators but haven't tested it at all. I only did half the trip it was just horrible. Even on the great surface recently redone the fork was pattering so bad I was getting dizzy from the bouncing, way way worse than the Cer in the 3c. So thats tomorrows job, the same adjustments I did to the Cer forks. I expect there is the same 1 hole and 3 turns on the emulator.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 21, 2016, 02:11
Well that was an easy fix, the 38mm Maz forks,yes not 35, I think have the same emulators as the 38mm Maz forks on Laverdas. These were fitted about 8 months ago and were considerably different to the 10 year old ones in my Cer forks. The latter ones have 4 slow speed compression holes marked already,2 were drilled and 2 were just dimpals. So I checked the spring,definitely blue, to see what they were set at. Bearly 1 turn of preload. That explained the bouncing,
they had hardly any high speed compression damping and with the 2 holes of slow speed. So I went to 2 1/2 turns and did a test ride. Way better, no bouncing. Firm but not uncomfortable. There staying at that for now. So thats another with 2 holes, seems the later emulators have 2 holes and the early ones have 1 hole.
Title: Re: Harsh Cer Forks.
Post by: Brett on May 21, 2016, 06:25
I did something dumb, I changed 2 things at once. I like a nice soft compliant suspension so while in there I backed off the emulator 1/2 a turn,wish I hadn't. I liked it better at 3 turns. As I had hoped the emulator did have 1 slow speed compression damping hole, 7/16 of an inch. O shit I forgot I only do Imperial drill bits,here comes Brett's I told you so, we have an Imperial Metric argument going. So I drilled another 7/16 hole 180 degrees away and took the bike for a spin around the block. Its definitely more compliant to small road irregularities, feels a lot more comfortable
on the small stuff, but a far bit worst with the spring preload backed off.Back in I go.
So guess you didnt need the holes to be accurate is that correct ? Just remembering back to the last time I gave you an measurement of 4 1/4 inch you told me it wasnt accurate...
But wait where are racetech valves made oh yes the last bastion of real measuring...
Title: Re: Harsh Cer Forks.
Post by: Vince on May 21, 2016, 07:39
Walked right into that, just like tyre pressures I just seem to stick with Imperial for drill bit sizes. 7/16 is a tight hole for the usual self tapers,1/8 is snug and 9/16 is a clearance hole.To many years doing it to change.
Title: Re: Harsh Cer Forks.
Post by: Laverda SF on May 21, 2016, 07:53
Ceriani's do tend to be harsh - Generally I use 15W in my 35 Ceriani's for Hwy cruising but should use 10W when it comes to pot filled winding roads where 15W is very harsh, spending time on the pegs, and 10W is smoother but somewhat wobbly.

Depends were you spend most your time riding. I suppose somewhere between 10 to 15W is best over all - Which I've never come to a conclusion, other then tire pressure is important.

Did I say anything - LOL

Title: Re: Harsh Cer Forks.
Post by: Lav the impala on May 21, 2016, 13:51
Walked right into that, just like tyre pressures I just seem to stick with Imperial for drill bit sizes. 7/16 is a tight hole for the usual self tapers,1/8 is snug and 9/16 is a clearance hole.To many years doing it to change.

Youíve lost me, 7/16=11mm, 1/8=3.2mm, 9/16=14mm. maybe you mean 7/64 and 9/64.

jacko.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 21, 2016, 14:06
yep thats what i ment
Title: Re: Harsh Cer Forks.
Post by: Lav the impala on May 21, 2016, 14:21

that's why metric is easier.
Title: Re: Harsh Cer Forks.
Post by: Brett on May 21, 2016, 21:50
that's why metric is easier.
each to their own I guess !!

But I agree that 7/16 does seem a tad big... by the by 7/16 is actually a tad over 11mm same for 9/16 is a bit bigger than 14mm no wonder there are so many nuts and bolts out there with rounded edges.... the disdain of my life people using the wrong tool for the job in hand.
Guess Vince uses a 7/64 bit as would have a hell of a time finding a 2.77 drill bit...

No back to the fork thingy...........................no doubt we will have an update on all this later today......
Title: Re: Harsh Cer Forks.
Post by: Reggie3cl on May 21, 2016, 22:25
Reminds me of a story Marty Moose, I think it was, related (bit hazy on the details, it was a while ago) where he was in a lift or something with a couple of popsies one of whom remarked that he was a big bloke and how tall was he exactly.  I'm 6 foot 6 (or whatever he is) he replied.  What's that in young person's measurements asked the popsie, presumably making him feel very old in an instant.
Title: Re: Harsh Cer Forks.
Post by: Laverda SF on May 22, 2016, 05:12
I simply things and convert inches and metrics into thousandths.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 23, 2016, 06:09
You're all mere youngsters. I use cubits.
Title: Re: Harsh Cer Forks.
Post by: Brett on May 23, 2016, 12:41
You're all mere youngsters. I use cubits.
I used to have a rubic's cube and a slide rule,  does that count :o
Title: Re: Harsh Cer Forks.
Post by: Vince on April 14, 2017, 03:52
Last weekend we did a ride on one of the more notoriously bumpy roads around Sydney, Wisemans Ferry and my forks are still harsh, earlier in this thread, Steve B mentioned my Emulators should have blue preload springs and I replied mine had no colour but I expected they should be blue and correct. I just had some emulators fitted to my Pantah and they came with blue springs. All the fitting info on the net says typically blue was the best starting point, so I got some blue springs on spec.
Cheap at $18 if they were the same as I had fitted. So today I swapped them out, I don't know what I had fitted and spent months adjusting including oil weight changes with minimum effect on the problem but compared to the blue springs which I can with some effort close with finger pressure the original springs I cannot move at all. MUCH stiffer. Haven't ridden it yet but from what it feels like it will make a huge difference. Hoping the fork kicking off big bumps is now gone.
Title: Re: Harsh Cer Forks.
Post by: Shajota on April 14, 2017, 04:06
Last weekend we did a ride on one of the more notoriously bumpy roads around Sydney, Wisemans Ferry and my forks are still harsh, earlier in this thread, Steve B mentioned my Emulators should have blue preload springs and I replied mine had no colour but I expected they should be blue and correct. I just had some emulators fitted to my Pantah and they came with blue springs. All the fitting info on the net says typically blue was the best starting point, so I got some blue springs on spec.
Cheap at $18 if they were the same as I had fitted. So today I swapped them out, I don't know what I had fitted and spent months adjusting including oil weight changes with minimum effect on the problem but compared to the blue springs which I can with some effort close with finger pressure the original springs I cannot move at all. MUCH stiffer. Haven't ridden it yet but from what it feels like it will make a huge difference. Hoping the fork kicking off big bumps is now gone.
Interesting - I have just been reading anything I could find on issues with the Emulators as I am still unhappy with low speed harshness and wondered what was best way to go and found a post on some other (US) forum about exactly this issue.
This bloke had been talking with someone from Race Tech about his low speed (& initial) harshness and they said the emulators come with a yellow spring (64lb) and he should change to a Blue spring (40lb) which would be more compliant and help his problem !!
So, this certainly looks like a logical next move - did you get the blue springs from Race Tech Vince?
Thanks - I look forward to giving this a go :)
(Of course I'll be buggered if I pull my Emulators out and they already have Blue springs ???)
Title: Re: Harsh Cer Forks.
Post by: Vince on April 14, 2017, 04:20
I got them from the Oz distributor Shock Treatment in Sydney, they do mail order, my Laverda emulators have been in for a very long time. Maybe 10 years, and they came with 1 slow speed bleed hole and these very strong no colour springs. That's Cer forks, the ones I recently bought for the Maz 38mm fork on my Pantah came with blue springs and 2 slow speed bleed holes standard so I guess over time they have had some feedback and maybe now have better std base settings. The first set I fitted were to the 43mm MX non-cartridge Kawasaki forks I fitted to my Husky Auto dirtbike and that was fantastic right out of the box, must have arsed that at first fitting.
Title: Re: Harsh Cer Forks.
Post by: Shajota on April 14, 2017, 05:00
I got them from the Oz distributor Shock Treatment in Sydney, they do mail order, my Laverda emulators have been in for a very long time. Maybe 10 years, and they came with 1 slow speed bleed hole and these very strong no colour springs. That's Cer forks, the ones I recently bought for the Maz 38mm fork on my Pantah came with blue springs and 2 slow speed bleed holes standard so I guess over time they have had some feedback and maybe now have better std base settings. The first set I fitted were to the 43mm MX non-cartridge Kawasaki forks I fitted to my Husky Auto dirtbike and that was fantastic right out of the box, must have arsed that at first fitting.
Yeh, just had a look at that post I dredged up and it is quite old so possibly things have changed. (mine are only about 5 years old) I can't remember what colour springs were on mine so will wait till I take them out again to work out next course of action.
Title: Re: Harsh Cer Forks.
Post by: Tippie on April 14, 2017, 06:08
Good to see this here now as I am getting my road bike ready to de-hibernate after winter. The emulators I fitted to my SF2 five years or so ago also had yellow springs as fitted. The info sheet with them said that for 33-35mm forks blue were recommended. Yesterday I backed off a turn but Iīll whip them out today and fit the blue ones. I also have the initial harshness on sharp bumps. I searched for this thread of Vinceīs and couldnīt find it. My racebike has the yellow as fitted and I donīt notice the initial harshness.
Title: Re: Harsh Cer Forks.
Post by: Vince on April 14, 2017, 07:07
On smooth roads the bike with whatever the stronger spring in it was fine, didnt bottom on the brakes. On bumpy roads it was ok, didnt deflect the steering but before I added the 2nd slow speed breed hole I would feel rapid pulsing in the handlebars usually approaching bends or traffic lights. That was I think small corrugations caused by heavy vehicles braking. On badly bumpy roads it would have big bangs go through the bars with quite a jar. Anyway be interesting to see how its going now.
Title: Re: Harsh Cer Forks.
Post by: Davo on April 14, 2017, 08:44
- did you get the blue springs from Race Tech Vince?


Whwn I bought my emulators they came with yellow springs fitted and a set of blue springs in the pack.
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 14, 2017, 11:58
Hey Vince I think we have been chasing the same problem.

I've found the forks harsh from the beginning with the sportsvalves fitted.

The problem is one day they feel better then another day they don't. I like firm forks, hate any real discernable dive but I also hate the slow speed bumpy ride.

I've adjusted the sag via preload using washers and the oil is the 5w recommended by Sportsvalve, now I'm slowly backing off the compression damping and putting in a little more rebound which makes the front feel more precise.


Title: Re: Harsh Cer Forks.
Post by: Vince on April 14, 2017, 12:42
That's why your gadget is better than my gadget. I only have the ability to mechanically adjust compression, rebound on mine needs an oil weight change for rebound. I have pulled the emulators out changed and back in to 20 minutes. What it feels like doing a front brake on fork push while standing next to the bike has it more progressive at bottom of travel, probably wishful thinking though. Will know more after a bumpy ride.
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 14, 2017, 14:13
Just another variable to confuse the situation!
Title: Re: Harsh Cer Forks.
Post by: jotacorsa on April 14, 2017, 15:05
I believe all the emulators ship with yellow springs and blue ones are enclosed in the package.
They now have 2 bleed holes and a pair of dimples for the user to add one or two more holes.

My Mirage originally only had a single bleed hole in the emulator but after a long trackside visit with Matt
(the Race-Tech tech) I added another bleed hole.

My std setup is blue at 2 turns, .95 springs with 25mm preload, 15w oil, two bleed holes for a 180-200# pilot
For someone in the 220-250# range I start with three turns on the blue spring and 5 to 10mm more preload
Heavier bikes (and riders) get more slow speed holes as they typically use the stronger (yellow) springs.

Title: Re: Harsh Cer Forks.
Post by: Dellortoman on April 15, 2017, 00:17
Is that a 200 kg rider?  :o
I thought I was a fat bastard  :D
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 15, 2017, 13:35
Still chasing mine today, no progress really. Brakes got in the way so never finished the tuning but was going in the wrong direction. Start again tomorrow.
Title: Re: Harsh Cer Forks.
Post by: Vince on April 17, 2017, 04:35
Just checked the front sag, it's been ages since I did it and was concerned it might have sacked out a bit. Its 37mm, close enough for me. Hopefully, my new front tyre should arrive soon and maybe even the not available in OZ but I talked the OZ distributor into bringing some in, T30 Evo 140/70 Bridgestone Radial rear. First time I have had a matched set of tyres for a very long time.
Title: Re: Harsh Cer Forks.
Post by: Davo on April 17, 2017, 04:46
This thread reveals the irony of chasing down a fault that doesn't really exist in the first place. The Ceriani forks were a perfectly good product as originally fitted to the bike. Certainly they were way better than any forks fitted to the big Jap bikes of the day. I too got caught the fork "improvement" bug, especially after I had to rebuild the forks with new pistons as one had swollen and was binding. I should really have just rebuilt them as they came out of the factory but after reading all the gushing posts on emulators and the Laverdamania article explaining how much better they were with emulators, I bought and fitted a set in the recommended manner - as per Laverdamania and Racetechs instructions.

You guessed it - forks as harsh as all crap. Now Racetech say you need adaptors to go with the emulators - not originally recommended, and need to be fitted with Racetech springs.

I wish I had left the f'n things alone as they were perfectly good forks for the bike in the first place and will never match modern cartridge forks no matter what you do to them - apart from converting them to modern cartridge forks. Pity I have drilled the damper rods and now can't go back.
Title: Re: Harsh Cer Forks.
Post by: Vince on April 17, 2017, 05:04
What sold me was the first set I fitted to the Husky dirtbike with the what I really wanted disc brake fork. That fork was a really good MX fork but absolute crap on little square edges bumps. The emulators made a huge difference, great on big hits and really comfy on the little stuff. I must have lucked out on that fit hitting the tune first time on the Rack Tech supplied original setting. On the Laverda, I have had the wrong preload springs fitted for 10 years. Even when I bought the blue springs the bloke who sold them to me was saying he preferred the yellow ones and recommended them. I just think they don't keep records or follow up on what works in what application and leave it all to the customer. The odd thing is the emulators I fitted to my Pantah 6 months ago, 38mm Maz, have the exactly correct setting std as supplied I have now in the Cer forks in my Laverda. Anyway with this thread at least we have a few different perspectives on these and people can make up their own minds. They should be plug and play after all these years of being around. I know both Brett and Marty have canned them over the years. BTW I expect you could either Epoxy or braze your holes and go back to std if you want.
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 17, 2017, 08:19
+1

Well having thought I'd cracked it yesterday, today I take the bike out and it was like riding a different machine - not a better one. Spent another hour up and down the coast with nothing particularly positive to report, just the same but different.

Need to do some more homework, there must be a way of making this work.
Title: Re: Harsh Cer Forks.
Post by: Tippie on April 17, 2017, 08:28
"forks as harsh as all crap." That sounds pretty much like sports suspension from the ī70s as fitted to Lav and Duc.
You are dead right Davo that getting the originals set up properly and working as well as they can is satisfactory. My own experience showed that replacing worn rebound valves (the stepped washer, I spun new ones up on the lathe that sat well into the damper rod) made them very good. However you still have both rebound and compression together reliant on oil viscosity. The emulators allowing these to be independent allows also all the possibiities to get it wrong. As this thread shows, playing with suspension can be like mud wrestling. Chasing "handling" problems is just as fraught as tuning problems. This thread is great for us who do want to play the game to set a benchmark. I have had them in my road SF for quite a few years and reckon they are great, the roads here in Norway have lots of big step bumps from water under the road freezing and expanding in winter and with emulators the forks cope much better with them. A bit of kickback from small sharp bumps is the only issue for me, and if fitting the lighter springs fixes it then Iīm happy.
For me the big issue with these forks is stiction as they donīt have teflon guides.
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 17, 2017, 10:14
This thread prompted me to go back to the box to check the spring rate.

Now here's a (potentially) stupid question, from the instructions I found on the box.

(https://lh3.googleusercontent.com/7tqAGc69z0_HrcfwoKAGVQoDfJFJlTNarRDt7h8x_1ZtgArgRF5gfq2MnCyQ1_s8bBXEidYoGj2loCxSin7VUGKb6fZAgzO-zwZPRHcDu6cQXQGRGvGkGE1TJoJk7uJwN9zJew=w800-h600-no)

To fit my springs I just opened the shock by taking off the cap and put the new spring in.

Also 100% sure I was told to put the spring in with the tightly wound section at the top. The instructions above say put that at the bottom. (Unless the instructions were written for upside down forks).

Anyway have I missed a trick here?
Title: Re: Harsh Cer Forks.
Post by: Davo on April 17, 2017, 10:32
"(Unless the instructions were written for upside down forks)." I think you are confusing forks with shocks. The Ikon 7610 is a rear shock absorber with an external spring.
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 17, 2017, 10:41
Hmmm victim of recycling!!
Title: Re: Harsh Cer Forks.
Post by: jotacorsa on April 17, 2017, 16:11
Davo, some sort of adapter is required to fit an emulator to the top of the damping rod. you can use any springs that fit.

Tippie, a neat trick with the ceriani is to fit the alloy bit, with the teflon ring, from the marzo fork, to the top of the damping rod
to reduce stiction. you could also machine a groove in an adapter to take a teflon ring. i suspect there is the suitable ring in use in an automatic gearbox somewhere for pennies. i'll see if i can find a pic.

Cam, in this part of the world the # denoted pounds not kilos. sorry for any confusion
Title: Re: Harsh Cer Forks.
Post by: Tippie on April 17, 2017, 16:21
The stiction I refer to is between the stanchion (downtube) and slider, but it is a good idea of yours for stiction between damper valve and stanchion.
Title: Re: Harsh Cer Forks.
Post by: Davo on April 17, 2017, 16:56
Davo, some sort of adapter is required to fit an emulator to the top of the damping rod. you can use any springs that fit.


That is now the case but was not so when I originally bought the emulators for Ceriani forks. It was definitely not mentioned on the Racetech site and if you look at the Technical pages on Laverdamania to this day it still only mentions the need for adaptors for Marzocchi forks only. In fact, the first time I read anything about emulators came from this forum after Vince commented that he had found out about them from the Racetec technician at a meeting somewhere.

The original adaptors for the Marzo forks were to allow the emulator to seat properly on top of the damper rod, which was not required for the flat top of the Ceriani rod. The adaptors they now recommend for the Ceriani forks have a seal that stops fork fluid passing around the emulator and have nothing to do with the emulator seat on the rod - a completely different function.
Title: Re: Harsh Cer Forks.
Post by: Vince on April 17, 2017, 17:24
That was Paul Thead, Mr Race Tech at Wakefield Park race track. We went to a track day to watch Crispin sort his Space Frame and Paul was in the next pit, he comes to OZ ever year to do Suspension Seminars. It was hard to follow we he was on about but it involved a Teflon seal that forced all the oil through and not past the emulator.
At the time, maybe 5 years ago they had a bit made to do this for 40mm Husky forks. I never did get any info direct from Race Tech USA from my emails but the local bloke in Sydney did something for me. On mine its something below the emulator that this seal was fitted to and I haven't seen it since it was fitted?
Title: Re: Harsh Cer Forks.
Post by: Steph on April 18, 2017, 14:42
Here is a (bad) picture of an adaptor (required for Ceriani forks) I made machined with a Teflon ring.

Cheers,
Stťphane
Title: Re: Harsh Cer Forks.
Post by: Vince on May 01, 2017, 06:31
I finally got a chance to try the fork out and it's very very nice, firm but no discernable shocks coming through the bars. Will try it out on a longer faster test at some point soon.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 14, 2017, 03:30
After last weekend long day ride that included a great bike road, 30k or so of not so smooth dirt farm tracks and an hour of slow traffic splitting I am much happier with the Cer fork on my 3C. Firm but nice and compliant.

So I now tried the same setting on the 38mm Maz fork on my Pantah expecting similar results. It's way worse.
I have a pair of Maz Symbols shocks on the rear that I wasted some money on having rebuilt and wasn't so happy with the result so I borrowed a pair of Koni shocks of Jason to try. The first lap of my test track and I noticed the horrible bouncing that happened with a closed throatal, causing almost a sea sick feeling was considerably reduced with the shock swop. I checked to see if I had an out of round wheel or tyre it was that bad before the shock swap. Seems I need new better working shocks. So then I checked the fork sag and travel used. The fork action is harsh and choppy, well worse than the Cer fork with the same settings in my 3C. Sag is close at 30mm but I am only using 80mm of fork travel on this bumpy test track. Where is the other 30 or 40mm of travel, don't know if total travel is 120mm but will check. I am thinking maybe the suspension expert may have over filled the oil and its hydraulic locking? So next job is a fork oil change and checks of the oil height. Going for 150mm springs and emulators out. Here we go again.



Title: Re: Harsh Cer Forks.
Post by: Tippie on May 14, 2017, 06:41
You are doing lots of good research for us Vince. You seem always to go for as much oil as possible, using the fully inserted slider method, with as small an air gap as possible. On conventional damper rod forks I have always used the method where I fill enough oil to ensure coverage of the valves. I fill the forks and pump enough that all air is out, and then make sure that I cover the top of the valves by about a cm of oil. If I quickly extend the slider it should not suck air, with emulators I use a rod to push down on the emulator so that it follows the damper rod. Using this method I have found that the amount of oil I add is the same as specified for virtually any bike. I then check the airgap by the compressed slider method and add a bit to one side if necessary so that they are the same.
It is just a suggestion as you have tried so much with these forks.
I remember production race teams used to fill as much oil as possible to overcome some of then soft spring clearance problems with Japanese bikes, and it is the way to do cartridge forks.   
Title: Re: Harsh Cer Forks.
Post by: Vince on May 14, 2017, 07:06
Hi Tippie, do you remember what the distance was that you ended up at for air gap. I find it hard to believe mine have the oil level high enough to lose 40mm of fork travel but I don't see what else would do that? Couldn't be coil bound springs, the suspension bloke does know his stuff. Used him for years
Title: Re: Harsh Cer Forks.
Post by: jotacorsa on May 14, 2017, 14:09
I am using a 140 air gap on 38s
Title: Re: Harsh Cer Forks.
Post by: Tippie on May 14, 2017, 21:51
My bikes are 750īs so different length downtubes.
I noted down 215mm from the oil to the top of the downtube fully compressed had the allen screw on the emulator just covered. Was 230ml of fork oil. It always was 200ml without emulators. One is a racebike and one is a road bike and both work as well as I can expect from  Cerianis. I just fitted the blue springs as suggested to the roadbike as it could have taken sharp steps a bit better but otherwise it was fantastic. I might fit the blues to the racer but I just added 10mm more preload as it was bottoming under brakes. Will see how both bikes go pretty soon when the weather allows here in arcticland.
It is easy enough for you to give it a try.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 16, 2017, 15:13
So I blow the fluid out of the 38mm Maz forks today, with zero fluid in them I still only get 80mm of travel so the restriction definitely isn't the fork Hydraulically Locking with too much fluid. I think from memory the springs are preloaded about 10 to 15mm so I doubt that also why I have so little travel. I will pull the springs tomorrow and find how much the forks can move with the caps and springs out, I expect that to be at least 110mm or a bit more.Don't know what's going on with this missing fork travel?
Title: Re: Harsh Cer Forks.
Post by: Vince on May 17, 2017, 07:11
Caps off and springs out I get 130mm of fork movement with no restrictions. Spoke to the suspension guru and he said cannot be coil bound, to be honest, the main spring is too light for my weight but there the heaviest available and it has zero preload anyway. This makes no sense at all so it's going out to him to see why it's defying the laws of physics. I want my 50mm of missing travel and a more compliant fork.
Title: Re: Harsh Cer Forks.
Post by: Brett on May 17, 2017, 10:25
Thought you bike had Ceriani's on it and that you had sorted it... way too much time on your hands Vince me thinks.
How did you get on with Roger did you make a date for the club ?
Title: Re: Harsh Cer Forks.
Post by: Vince on May 17, 2017, 11:13
Haven't spoken to Roger yet, this is now the Maz forks on the Pantah. The Laverda Cer forks are way better now. Seems the Laverda emulators have had the stronger green, in my case no colour, springs, replaced them with the blue springs and it now nice and compliant. Unlike the 38mm Maz forks in the Pantah. Today I was thinking maybe I had the wrong wheel spacer fitted when my mate did the 35mm to 38mm fork swap 30 years ago but a trip to Gowys confirmed Its got the correct wheel spacer and that wasn't the cause of the binding issue.
Title: Re: Harsh Cer Forks.
Post by: Grant on May 17, 2017, 12:28
Are the fork legs straight and parallel,  yokes bent?
Off the bike the forks are still stiff/short stroke or freely moving compared to when on the bike?
Fork brace fitted?
Just trying to think laterally. 
Title: Re: Harsh Cer Forks.
Post by: Vince on May 17, 2017, 12:44
Appreciate the thought, legs are brand new.Haven't had them off the bike, they move with the fibreglass guard and wheel attached reasonably easily together given the weight to full, 130mm travel with the caps off. No brace fitted. Anyway its back to the suspension guro on Monday.
Title: Re: Harsh Cer Forks.
Post by: Brett on May 17, 2017, 13:22
I thought you were the suspension guru Vince ?????????now I am confused...
If you put one sping in one side what happens.. better still if you put the original springs back in then what ?  as its either the springs or something up with one of the damper rods.

Perhaps your suspension guru flogged you the wrong springs. Better you get him to sort out your leaking rear shocks also but to be ready for the trip or are you taking the Pantah ?? though if it were me would send the shocks to Proven Products even with postage reckon it will be cheaper.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 17, 2017, 13:42
He doesn't do twin shocks, BTW the Laverda shocks are ok. Oil came from the head issue. Why this is happening to the Pantah forks makes no logical sense, the springs are softer than std and there appears to be no solid contact internally but something is restricting movement.
Gravity waves maybe?
Title: Re: Harsh Cer Forks.
Post by: Brett on May 17, 2017, 13:46
Again if you the stock springs back in do you have the issue and why are we talking Ducrapy on a Laverda forum anyways.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 18, 2017, 06:45
Must have missed seeing all those Marzocchi forks fitted to Laverdas. So today after Brett's suggestion, helpful as always, I pull a spring out and tried it with one spring fitted and both caps on. Did this to both sides to see what might happen. Rolling off the centrestand I was concerned the bike might fall to fully bottomed forks but nope. It went down a bit and stopped but with a pushdown and the brake on it will bottom with either spring out pretty easily. Yes a complete waste of time doing this, what could I   learn from this. Seem my problem isn't the springs, or some mechanical resistance but I think its sticktion. There appears to be one hell of a lot of this restricting smooth movement and it gets stronger as the forks compress.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 18, 2017, 07:49
Seems you've invented progressive stiction Vince. I reckon you should patent it.  :D
Title: Re: Harsh Cer Forks.
Post by: helicopterjim on May 18, 2017, 07:55
Seem my problem isn't the springs, or some mechanical resistance but I think its sticktion. There appears to be one hell of a lot of this restricting smooth movement and it gets stronger as the forks compress.

I think you need to pull the forks off and find out what's really going on ...... you don't want to be damaging them if it is a duff bushing or something like that.
Title: Re: Harsh Cer Forks.
Post by: Grant on May 18, 2017, 10:55
As Cam says, it doesn't look like stiction.
Stiction is static friction that resists the initial movement of the item, in this case the fork slider.
After that it is dynamic friction.
Something that resists movement in an increasing manner must be caused by some other source.
Title: Re: Harsh Cer Forks.
Post by: AndyW on May 18, 2017, 11:11
Something that resists movement in an increasing manner must be caused by some other source.


A combination of damping and progressive air compression...?
Title: Re: Harsh Cer Forks.
Post by: cbertozz on May 19, 2017, 00:32
If I remember rightly you tackled the flow of oil earlier in this thread. My suspension guy had to make a collar to seperate the valve from the bottom of the damper rod because it was sitting right on the end and restricted flow. Works much better now (relative).
Title: Re: Harsh Cer Forks.
Post by: Vince on May 19, 2017, 01:04
Even with the forks empty of oil, it doesn't move past 80mm of travel with both springs in, with only one spring in it moves 130mm. And that's with lighter springs than I should have in it.On the road with oil in them even with me hitting speed bumps on the brakes stupidly fast it only used 80mm of travel even if it should have 130mm and is very harsh and its been like that for the 30 years I have known the bike. I used to say to my mate the previous owner, you need to do something about how hard the suspension is. Seem It's down to me.Its going back to the suspension guru on Monday, maybe he can find something
Title: Re: Harsh Cer Forks.
Post by: AndyW on May 19, 2017, 04:55
Even with the forks empty of oil, it doesn't move past 80mm of travel with both springs in, with only one spring in it moves 130mm. And that's with lighter springs than I should have in it.


Sounds to be that the springs are too long/heavy or both. How do you know the springs are lighter than should be in it and how do you know the intention of the manufacturer was for all the travel to be available? Might it have been set up for racing on a smooth surface?
Title: Re: Harsh Cer Forks.
Post by: Vince on May 19, 2017, 06:33
The springs are marked with either 90 or 95 and a serial number.From memory that's the stiffest springs available for 38mm forks.They are 360mm long with no preload, the caps require zero push to get on. I know its sounds exactly like the springs are to stuff but there the same as are in the Ceriarni forks on my 3C and work ok in it. I wouldn't mind some minor bottoming resistance 10 or 15mm where it would need to be ridden into a 150mm concrete gutter to be used but 50mm of resistance isn't reasonable. There, not some oddball forks from what I can see, how much travel do other bikes with 38mm Marzocchi typically use, it's not hard to see with a cable tie fitted. The last long ride I did last year on a 40c day at 600ks down to the Southern Highlands had me beaten to a pulp from the suspansion. I like riding it and would if it wasn't so uncomfortable.
Title: Re: Harsh Cer Forks.
Post by: Gravelroad on May 19, 2017, 15:27
Vince, are there venting valves in the fork caps of your Pantah, which could possibly be blocked??? I had more or less the same issues as you describe, with the 35mm Marzo forks on my Morini. It took not many k's for myself being totally beaten up by the harsh fork behaviour, with things getting worse as longer I was into the ride. Changed oil, played with air gap and pretension etc., all to more or less no avail. Finally, I had a closer look on the fork caps, to find out that they include a kind of venting valve. Unlike the Ceriani on the triple, the Marzo on the Morini seemed to be a "vented" fork. Those vent valves are formed by a simple hole in the center of the caps, with a steel ball sitting at the bottom of the hole, followed by a spring, sized similiar like the ones you'll find in ball pens, all held in place by a countersunk slotted screw, sitting at the bottom of the allen key hex of the cap. I wondered how the air could go past the tapered seat of the screw head. Close inspection reveiled, that these countersunk screws are of a special type, having some ridges on the tapered seat of the screw head, to let the vented air pass by. This ridges had simply worn flat, blocking air passage, and taking the vent valves out of work. Slightly releasing the bolts to enable air passing by the bolt head instantly cured the harshness on that forks.





Title: Re: Harsh Cer Forks.
Post by: Vince on May 19, 2017, 15:46
The caps on mine have a Shrader valve, same as a tyre valve. There set at an offset angle on top of the cap with a steel valve cap on top. I depressed them to see if any air pressure had built up, there was a tiny bit released. They look completely sealed, don't know how they might relieve air pressure and not squirt out oil on compression. With them open, it would stop any air compression that usually is used to resist bottoming. I wonder if there should be some form of active air bleeding from them. I will try having them depressed while bouncing the forks hard and see how much travel there is then.
Title: Re: Harsh Cer Forks.
Post by: Gravelroad on May 19, 2017, 22:00
Hmm, never seen them with Schrader valves on the fork caps, that might be aftermarket items? You could also remove the valve inserts and put the valve caps back on loosely for a test.

Just went down to the shed to take some photos of the Morini's vented fork caps. See pictures added below.
First picture shows the vent hole at the center of the pin at the inside of the fork cap. Second picture shows the cap from the top with the countersunk slotted screw sitting inside the allen key hex. Third picture then shows the spring and the ball sitting under the screw. Looking closely at the seat of the screw, you can spot the remains of the ridges, intended to allow air passing by the screw head. The slotted countersunk screws are a actually a standard item, my memory had played tricks with me here, so forget what a said about them in my last post.

Title: Re: Harsh Cer Forks.
Post by: Gravelroad on May 19, 2017, 22:07
Later variant of the Marzo caps had a different venting sytem, with the venting hole ending out in one of the flanks of the hex on top of the caps, see this picture at bevelheaven: http://www.bevelheaven.com/Products/late-marz-caps.jpg (http://www.bevelheaven.com/Products/late-marz-caps.jpg)
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2017, 06:54
So I finally got the call from the suspension guru. While I was there I was shown that a few kilos of lateral load on one fork while it was in a vice created huge amounts of friction that took a considerable push to overcome. I was told that without bushes they couldn't fix these forks to make them more compliant. So I asked how much to convert them to top and bottom bushes. They needed to find someone who could line bore or hone them and would get back to me. They said to supply bushes and machine to fit them,$150. Today I hear after calling a few places they found someone to line bore them at $400 a fork, all up $1200 to convert to bushes to reduce friction. So there going back together as they are. I have no idea what to make of all this. All I want is the full 130mm of travel and a nice compliant ride. Seems it's not going to happen. Again these are the 38mm Marzocchi forks wheel axle in line with the fork on my Pantah, the 38mm Cerianis are now great on my 3C.
Title: Re: Harsh Cer Forks.
Post by: Grant on May 24, 2017, 08:25
Cheaper to buy another pair of original forks.
Title: Re: Harsh Cer Forks.
Post by: breganzane on May 24, 2017, 08:55
All I want is the full 130mm of travel and a nice compliant ride. Seems it's not going to happen. Again these are the 38mm Marzocchi forks wheel axle in line with the fork on my Pantah, the 38mm Cerianis are now great on my 3C.

Your cheapest and easiest solution will be a rechrome and grind of the stanchions (if required) and a set of new or good used sliders.  That will at least get it back to as good as they were when new.  Try Ian Gowanloch, he has a staggering selection of Ducati parts at his place near Tumut, and his prices are fairly reasonable AFAIK.
A conversion to a Jap fork would give a better result but with a lot more hassle, and likely cost if you can't make the stuff yourself. 
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2017, 09:13
Its got brand new stanchions, the old ones were rusty and even with the old ones it was harsh. The bike has only dome 30,000ks so I doubt its forks are warm out.
Title: Re: Harsh Cer Forks.
Post by: breganzane on May 24, 2017, 10:07
Its got brand new stanchions, the old ones were rusty and even with the old ones it was harsh. The bike has only dome 30,000ks so I doubt its forks are warm out.

Jap forks it is then.  Early GPZ1100 or early FZR400/600 - they're both good 38mm options.  The FZR ones might be almost close enough to try out with stock springs and damping on a Pantah, if that fails then just transfer the existing emulators and springs into the Yam forks (will require some engineering).  You'll need to sort out the axle/bearings/spacers situation, and sort out the caliper/disk combo via adapters or whatever.  Bit of a job really.
......
Or just flog the Pantah for serious coin, buy a few year old Monster for next to nothing and just enjoy!  :)
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2017, 10:45
One went for $20k at a recent auction, unbelievable but it was very nice
Title: Re: Harsh Cer Forks.
Post by: Grant on May 24, 2017, 12:16
Were the new stanchions genuine or replicas?
Title: Re: Harsh Cer Forks.
Post by: Jod on May 24, 2017, 13:02
Sell the Pantah Vince. You will hopefully get the bugs bunny for another Laverda...
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 25, 2017, 01:42
Sounds like you might have a bent slider Vince. They work OK independently but when bolted together through the axle, something binds. Have those forks ever been involved in a prang?
Title: Re: Harsh Cer Forks.
Post by: Vince on May 25, 2017, 02:50
The stanchions are brand new, lucky f they have done 300ks.Maybe the lowers have been down but I don't think so. I turned up at the suspension place last year to finally do the Emulator installation and was told they were too rusty so did a mad dash to Gowanlocks and bought new ones. They were $200 each so I expect not genuine. This morning I got some Facebook message thingy from an old site member from here who is doing the same thing except he is going full cartridge to a bevel twin. Small world and good info, last night this was at rock bottom.
For the $1200 quoted just to convert to bushes and not including the other $800 I have already spent on fitting Emulators and new Strachan's I could have bought a complete Monster front end with better brakes, lighter wheel and way better suspension and adapted that.
Nothing new to me as I have done exactly that to 3 other bikes with great results. I just expected this to be a way easier fix.







Title: Re: Harsh Cer Forks.
Post by: Vince on May 25, 2017, 03:18
I did notice some blistering on one of the bottom legs that face towards the wheel and isn't easy to see with it all together.There painted black, Maybe there is some casting issue internally.Last night I was thinking I might contact glue some 240 wet and dry on an old fork stunchan and attempt to see what some rubbing might produce deep down in the fork lower leg.
Title: Re: Harsh Cer Forks.
Post by: Grant on May 25, 2017, 06:37
I have heard stories that replica stanchions are not as well made as originals so I get used ones re-hard chromed.
If you attach sandpaper to an old stanchion how are you going to get it past the top bush without damaging it?
Title: Re: Harsh Cer Forks.
Post by: Vince on May 25, 2017, 07:31
You taking seal or bush, I didnt think there are bushes. I would take the seal out.Here is what I really don't understand here at all. The go to replacement fork for Guzzi's with that oddball sealed damping and those that wanted stiffer front ends is exactly what I have, a 38mm Marzocchi fork. I am finding it hard to believe my reduced travel harsh fork is typical of all 38mm Marzocchi forks. It must be only my fork, I find it imposable to believe there all that bad.
Title: Re: Harsh Cer Forks.
Post by: Legs on May 25, 2017, 07:50
Found that the diagonally split nylon seals around the pistons had swollen and were causing a bit of friction, nipped about a mm off and the forks consequently have a much smoother action; the lowers now drop under their own weight (springs removed of course).
Title: Re: Harsh Cer Forks.
Post by: Jod on May 25, 2017, 07:57
A1 Hardchrome in Silverwater will redo your old ones for $300 cash. Better than buying new ones as they put thicker chrome than repros...
Title: Re: Harsh Cer Forks.
Post by: Grant on May 25, 2017, 08:30
The bush in Marzocchis is actually an integral part of the casting.
If there was no bush there would be a lot of play in the set up.
More of a locator/guide than a bush, but still a bush of sorts.
Wear that away with sandpaper (when inserting your sandpaper/stanchion combo) and you stand the chance of wrecking the slider in a new way.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 25, 2017, 08:36
It would be an attempt to smooth out any resistance or casting flaws. It's just an idea at the moment.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 25, 2017, 10:11
I did notice some blistering on one of the bottom legs that face towards the wheel and isn't easy to see with it all together.

Maybe that fork slider suffered a ding at some stage in its life, perhaps before you owned the bike. Before you start poking abrasive stuff down the fork leg, is there some way to measure the ID of the slider tube in various positions?
Perhaps there's a restriction at a particular spot.  If your suspension guru can't work it out, then perhaps he isn't such a guru.
Title: Re: Harsh Cer Forks.
Post by: Grant on May 25, 2017, 10:32
It would be an attempt to smooth out any resistance or casting flaws. It's just an idea at the moment.

I know what you are trying to do, but you will not get your sandpaper/stanchion past the 'bush' without damage.

If you slide a bare stanchion down each slider is there a point at which there seems to be a sticky spot?
If not then you are pissing against the wind trying to rub something away that the stanchion can't find.
Title: Re: Harsh Cer Forks.
Post by: Shajota on June 15, 2017, 05:56
Hmm, never seen them with Schrader valves on the fork caps, that might be aftermarket items? You could also remove the valve inserts and put the valve caps back on loosely for a test.

Just went down to the shed to take some photos of the Morini's vented fork caps. See pictures added below.
First picture shows the vent hole at the center of the pin at the inside of the fork cap. Second picture shows the cap from the top with the countersunk slotted screw sitting inside the allen key hex. Third picture then shows the spring and the ball sitting under the screw. Looking closely at the seat of the screw, you can spot the remains of the ridges, intended to allow air passing by the screw head. The slotted countersunk screws are a actually a standard item, my memory had played tricks with me here, so forget what a said about them in my last post.
Anyone have any tips on how to get that slotted screw undone?
Reckon mine will be guncked up so the venting won't work. I put a probe into the hole underneath and was able to push the ball against the spring although intitially it felt stuck to. I'd say well worth a clean out but that screw doesn't want to budge.
Title: Re: Harsh Cer Forks.
Post by: Vince on June 15, 2017, 06:20
After a long soak in your favourite penetrator, maybe one of those Impact tools you hit with a hammer. They were the tool of choice years ago for those soap like Philips case screws on Japanese bikes.
Title: Re: Harsh Cer Forks.
Post by: Shajota on June 15, 2017, 07:00
After a long soak in your favourite penetrator, maybe one of those Impact tools you hit with a hammer. They were the tool of choice years ago for those soap like Philips case screws on Japanese bikes.
Yeh, used to use mine all the time on my Honda 4 in the mid '70's............. ;) (still have the same impact driver too,........)
Just a bit dodgy about taking a hammer to the forks. Actually I have the forks out and caps off at present so have been trying to hold the cap in a vice (with suitable padding) but that aint gonna be enough for an impact driver. Guess I may have to put back together and try. Anyway will persevere and see how I go...............
Title: Re: Harsh Cer Forks.
Post by: Vince on June 15, 2017, 07:17
Can you get a block of Hardwood under it in the throat of the Vice. It would be easy to butcher either the head of the screw or shear it off.
Title: Re: Harsh Cer Forks.
Post by: Shajota on June 15, 2017, 07:27
Can you get a block of Hardwood under it in the throat of the Vice. It would be easy to butcher either the head of the screw or shear it off.
All good, got em Vince. Found some industrial rust loosener that I acquired from somewhere, sprayed it around the top and pushed ball in and sprayed from below as well. Got some good leverage with a stilson on the screwdriver and they cracked. All good, nothing damaged..........Now just to work out best settings fro emulators and air gap and go again................... :o
Title: Re: Harsh Cer Forks.
Post by: Vince on June 15, 2017, 07:42
My Cerianis are at 2 1/2 turns of preload with the blue spring and 2 holes in the plate on the emulator, 15wt at 130mm springs and emulators out and fully compressed.
After doing The Thunderbolts bumpy way a couple of weeks back I am going to try 3 holes in the plate. I am pretty heavy though. The 3 holes will be about the end of my experimenting as that's about all I can do. If 3 doesn't work it's easy to maybe solder up the last hole.
It's great on reasonable roads but in real crappy roads, I still get some thumping through the bars on municipal small bumps.
Title: Re: Harsh Cer Forks.
Post by: AndyW on July 13, 2017, 08:58
After doing The Thunderbolts bumpy way a couple of weeks back I am going to try 3 holes in the plate.


So..., how did it go??
Title: Re: Harsh Cer Forks.
Post by: Vince on July 13, 2017, 10:37
Did nothing except re read
 
http://www.racetech.com/page/title/Emulators-How%20They%20Work

Seems the holes are low-speed compression and I need to work on high-speed compression, big square edged bumps, that's emulator spring preload. I think I made the mistake of using the same preload I had on the original to stiff spring, 2 and a bit turns and I think I need more preload now it has the softer spring. Would be a good test to try this before Sundays breaky run to the bloody bumpy Wisemans Ferry area. MUST PULL FINGER OUT.
Title: Re: Harsh Cer Forks.
Post by: cbertozz on July 16, 2017, 23:29
How did you get on?
Title: Re: Harsh Cer Forks.
Post by: Vince on July 17, 2017, 03:45
I didnt change anything, I have a leaking Icon shock that might make a difference, oil splatter on the wheel and maybe rear tyre.It was a bit loose in the rear later in the day. The fork is pretty close, but I will go 1/2 a turn harder just to see what will happen.
Title: Re: Harsh Cer Forks.
Post by: Vince on September 01, 2017, 05:21
Call me literal, we had a discussion about fork setup at the last club night and it got to sag versus spring preload. According to xxx, unnamed person, Terry Hays told him that all you need to do with the correct rated springs fitted was at add 10mm of preload and not to worry about sag measurements. So as an experiment I just did that. I had 10mm of washers stacked to get the 1/3 sag measurement. The less literal bit about this post is, I thought 10mm preload didnt include the fork cap screwing into the leg that adds 20mm of preload from said cap. So its quite a bit more compliant now. Be interesting to see if it reduces the kick I was getting on square edged big bumps on Sundays ride. Rebuilt Icon shocks fitted as well.I love to see what happens with any change for myself.
Title: Re: Harsh Cer Forks.
Post by: Vince on September 24, 2017, 05:20
Tried a couple of things on this Sunday ride, not the bumpiest road out of Sydney but it had enough to test what I had done. Last club night the discussion went to fork preload as one of the blokes had been doing his think on this. From the suspension bloke we both have used the latest thing is forget sag dimensions, just use 10mm spring preload so I gave it a go but did a sag measure to see what would happen. So with 10mm preload, that does NOT include the fork screw cap BTW
I got 47mm of sag. With my usual number of washers packing the spring,5. I got 36mm of sag. So it makes a fair bit of difference. I took a quick spin around the block with the lesser preload and didnt like the result, I have longer shocks and the forks through the trees and with this bigger sag it felt a far bit twitchier. The next experiment was after lots of thought as to what I was trying to dial out. On really big bumps the bike kicks hard and on smaller bumps into corners, I would get this small bouncing feeling through the bars. I am thinking I don't have enough rebound damping to absorb the spring effects, so I tried some 20 wt fork oil at my usual 130mm fork fully compressed and springs and emulators out and I really liked the result. Much reduced kicking of big bumps and no bounce that I could detect. There is an effect called packing where the fork reacts to a bump and doesn't return fast enough to deal with the next bump resulting in the fork freezing, didnt have this happen. Using heavier oil is the only way to slow rebound damping but it affects compression damping as well, I am at 3 turns of preload on the emulator and that's now too hard so its back to 2 1/2 turns and I will see what that does. This is a good result to me in this search for a compliant and working well for me fork. BTW I am a fat bastard at 125kg so this might not work for other applications.
After the emulator adjustment, I will try the reduced to 10mm preload again on a longer ride to check its effect




Title: Re: Harsh Cer Forks.
Post by: cbertozz on September 25, 2017, 14:42
Glad to see you're persevering!
Title: Re: Harsh Cer Forks.
Post by: Vince on February 06, 2018, 03:22
Its been a while so here are my latest changes. The last stuff I did had me a bit confused as to what weight fork oil I was at. Notes, not me. The last 2 rides I was back to feeling pulses through the bars from small square edged hits so I must have gone back to 15 wt as that allowed this to happen. So today I changed back to 20wt again and just to add to the confusion I also changed the oil level from what I have always used. That was 130mm, springs and emulators out and the fork fully bottomed. Now it's 160mm. I noticed some stichion when moving the fork to bleed the air out, so will try a light rub of 20 wt fork oil on the stanchions to maybe lube the seals and dust wipes a bit.I checked what full travel is and it came out at 125mm, with the old oil level I am using 95mm of travel so it will be interesting to see what happens with an air gap that was 130mm and now is 160mm.
Title: Re: Harsh Cer Forks.
Post by: Davo on February 06, 2018, 04:07
Old adage - never change more than one thing at a time when problem solving.  (banghead)
Title: Re: Harsh Cer Forks.
Post by: Vince on February 06, 2018, 04:13
Yes, usually. But. I had tried the 20 wt before and found an improvement in damping control over 15wt. According to the experts, air gap only affects the bottoming resistance and achieving full travel. So it will be reasonable to expect some data. Before the change, it was behaving just like when it had 15wt in it. Suck it and see works for me.
Title: Re: Harsh Cer Forks.
Post by: AndyW on February 07, 2018, 11:23
20wt? My wrists are aching at the thought of it... :o :o
Title: Re: Harsh Cer Forks.
Post by: Tippie on February 07, 2018, 11:36
Very interesting Vince. Itīll be good to hear the change with more air space. Enclosed air being a non linear spring, you could well have been running into some serious resistance there. From my experience less air gap causes resistance to bottoming, just as your experts say, as you are effectively introducing another spring. I still just go with keeping the oil comfortably over the dampers, and just the one spring to work with.
Title: Re: Harsh Cer Forks.
Post by: Vince on February 07, 2018, 11:48
I was also surprised at what effect 20 wt had, it took away all the small bouncing and pulses I was getting through the bars on your typical bike friendly backroads around Sydney and we have some shockers,pun slipped out.Its noticeably more comfy than the recommended from Race tech 15wt. It's going to be a while till I try the new air gap, rear wheel issues need fixing.
Title: Re: Harsh Cer Forks.
Post by: Vince on March 09, 2018, 05:33
Finally got a chance to do a quick 5-minute spin around the block and waste another day of my log book rego.
So I changed the fork oil hight from my usual 130mm springs and emulators out and fully compressed to 160mm, I expected to use more fork travel.Thats hitting all the crap around including big speed bumps and hydrant covers as hard as I could. With 130mm of airgap I was using 95mm of fork travel, and with 160mm I am now using 95mm of fork travel. Yep exactly the same travel, with the forks completely bottomed that shows 125mm available. I find this very surprising. I really expected there would be a difference with different oil hights. The action with the 20wt oil is fantastic.No shocks through the bars even on big potholes and a nice firm yet responsive action. Be good to know why that final 30mm travel doesn't come into play but I am very happy with what I have.
Title: Re: Harsh Cer Forks.
Post by: helicopterjim on March 09, 2018, 06:39
Interesting that you are having best results with 20 wt oil. I've been talking to Sports motorcycles about their kit and the say to start with 5 wt. and if you need to go past 10 wt. then you have other problems. Mind you .... their valves may look the same but they have both rebound and compression adjustment. Apples and oranges i suppose.
Title: Re: Harsh Cer Forks.
Post by: Vince on March 09, 2018, 07:20
My bet is it's down to the size of the holes, my Dirtbike uses 5wt and all modern suspension tries to use the lightest oil they can as it moves faster and easier.They want control of tiny movements, be great to achieve that but not on my budget. I am really surprised that in my case 20 wt works so well but that's with exactly my situation, size of holes and body weight. Getting no change after 30mm of change in fork oil hight does also surprise me. There are apparently noticeable changes with 5mm but not to me.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 13, 2018, 07:32
Lately, I have spat the dummy about how horrible the 38mm Marzocchi forks are,std were 35mm but not on this Pantah. So I finally finished this round of mods. I had the fork bottoms Hard Anodised as per the Race tech recommendations, fitted SKF green fork seals and dust wipers. I finally heard back from the US Race Teck bunch and got some advice from Matt their Vintage suspension bloke. He said I should try and extra 2 high-speed damping holes bringing it to 4 holes each emulator, the max you can do, extend the air gap 20mm to 160mm making sure when the fork is extended the emulator is completely covered by oil and that's where its at now. I did a quick spin around the block between freezing cold showers and its considerably better. You couldn't pick it doing the fork bounce trick but the front end now sticks well on bumps, I was confident to push it hard on bends. The only issue is its still only using 80mm of front travel.
That's hitting big speed bumps very hard. Has anyone else tried the cable tie on the fork trick and measured how much travel they use. Maybe that's all its got but they do move to 130mm when its bottomed and the springs are out doing the fork oil level.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 13, 2018, 10:46
I just shocked myself, I started this thread almost 2 years ago and its had 10,921 views. That's stunning. Now, who in that bunch has put a cable tie in a set of 38mm Marzocchi forks and found out that travel they use.
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 13, 2018, 12:35
Yep , guilty Vince ! On Jota with 10w oil - 280ml and new boingee things. Round 110mm of travel after Broadee Bonanza and some spirited riding with the Wrecker :D
Title: Re: Harsh Cer Forks.
Post by: Tippie on May 14, 2018, 10:45
Both my SF2s with emulators. The race bike bottoms out (sort of not surprising) and I have run up more preload on the main fork springs, emulators at standard (canīt remember, 2 turns preload?) and it is great, much more stable than it was before fitting emulators. The roadbike was fairly harsh, and wouldnīt use more than a bit over an inch of travel. I swapped to the light emulator springs, just the same. I have now backed off the emulator preload to zero preload, and now have 100mm travel with normal riding. I could probably run half a turn preload but it is so much better Iīll leave it for a bit. I havenīt gone drilling extra holes or anything.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 14, 2018, 11:33
Bit more testing to do but It seems I will be getting lighter fork springs, its got 0.95 springs now with bearly any preload and I am still only using 80mm of travel. Those springs work fine in the cer forks on my 3C. Take one spring out and the frontend move through 130mm of travel easily so nothing is binding. Weird.So with 35mm of sag and 80mm of travel its only got 50mm of effective travel on our crappy roads.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on May 14, 2018, 13:37
Big weight diff Vince.  You are still talking about the Pantah?
Title: Re: Harsh Cer Forks.
Post by: Vince on May 14, 2018, 22:23
yes there not that different weight wise
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 15, 2018, 00:54
yes there not that different weight wise

What..... a pantah weighs similar to a lav triple  :o :o
Title: Re: Harsh Cer Forks.
Post by: AndyW on May 15, 2018, 01:01
yes there not that different weight wise

http://www.motorcyclespecs.co.za/model/ducati/ducati_600sl_pantah.htm (http://www.motorcyclespecs.co.za/model/ducati/ducati_600sl_pantah.htm)

187kgs
Title: Re: Harsh Cer Forks.
Post by: Vince on May 15, 2018, 01:56
That was a dumb thing to say, I thought the Pantah would be 200kg approx. I have done the Race Tech spring test on their site and that supplies the bike weight and you add your weight and riding style and both the Laverda and Pantah came up with 0.95 springs. I didnt ask but that's also what Terry Hays supplied so I just expected they would be correct.Not so sure now. With one spring out the fork moves through 130mm easily, everybody including the Race Tech bloke in the US was expecting damping changes to fix it and they have made it much more compliant but still there is the missing 50mm of travel.
Title: Re: Harsh Cer Forks.
Post by: helicopterjim on May 15, 2018, 02:07
Try lighter springs.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 15, 2018, 02:30
That's a $180 test, but that's where it's heading. I just emailed Matt at Race Tech to ask how much softer.
Title: Re: Harsh Cer Forks.
Post by: helicopterjim on May 15, 2018, 04:41
I was just talking to a fellow who has Emulated a few bikes. He reckons that from his experience you need to go at least one spring rate lighter than what RaceTech recommends. His SV650 needed springs 2 sizes lighter.

Jim
Title: Re: Harsh Cer Forks.
Post by: Vince on May 15, 2018, 04:51
Here is Matts reply, so its flip a coin as to 0.8 or 0.85.That's quite a percentage difference to 0.95 that its got now.
I want all the travel I can get but I don't want it bottoming and needing huge amounts of preload either.


It appears you do have .95kg springs. Pretty firm for a vintage bike due to chassis geometry , fork friction, etc. It has been my experience more often than not vintage riders will prefer softer setup than that of comparable late model motorcycle.

I personally never install anything higher than .90kg in a bike for this type. However opionions vary, ask any 3 suspension guys & will get 3 different solutions. I cannot speak to road conditions in the land down under. As for USA riders I would install .80 or .85g rate for street riders, .90kg for vintage road race & setup at 15-25mm spring preload as needed to achieve desired sag & ride quality. If Gold Valve setup Blue #40 GVE Springs @ 2-3 Turns. Oil Level 130-150mm using 15wt as needed to use full fork travel & avoid undue bottoming.
Title: Re: Harsh Cer Forks.
Post by: Chris M. on May 15, 2018, 07:25
Vince, Racetech mention the standard as being 8.4 or something, but recommend 0.95 for canyon, what ever that is and 1.45 for the track. I went through this with my Jota and settled on 1.0 based on 100kg. At the time I weighed a lot more than 100kg and it was still a bit harsh so I'm never telling the truth ever again ....
 
On my bevel, that I'll have going again when my kids leave home, one side only was sticking at full compression. No amount of reaming with a piece of dowel and wet and dry could make them any looser and even Dave Kellett had a crack with a tool he invented for the job. So I wonder if a lot of Marzos and Ceriani forks stick because it's not pretty what's down inside the slider? When you throw in the tiny tolerances between the stanchion and the slider and that's supposedly taken up by the fork oil you feel like pulling your hair out.   

Sooo ticking off the 2 year long list one more time. Are the tubes dead straight and is the air gap a consideration?

I did come across a reference to some non Maxton drop in cartridges for these forks but in the end nothing will make then any better until you reduce stiction.     
Title: Re: Harsh Cer Forks.
Post by: Vince on May 15, 2018, 08:00
Hi Chris, the fork lowers were Hard Anodised and its got a set of SKF oil seals and dust scrappers so that's as far as I can go reducing sticktion. I just ordered a set of 0.8 springs, the US Race Teck vintage bloke said he has never recommended 0.9 and above for vintage bikes, so we will soon see how that goes. Looking past the limited travel it appears the damping is a lot more compliant after recent changes. There never going to be as good as modern stuff but hopefully there heading to a better place.
Title: Re: Harsh Cer Forks.
Post by: AndyW on May 15, 2018, 08:12
Hey Vince, Iím using 0.85 in my Mirage and Darmah. The guys here reckon the forks feel good and I reckon to be using about 100mm travel on an average ride out on SA roads: I donít see why you need to have full use of the travel all the time as itís always good to have a bit extra in reserve for that extra special bump or pot hole.. :o :o
Title: Re: Harsh Cer Forks.
Post by: chrisk on May 15, 2018, 09:00
Hey Vince, Iím using 0.85 in my Mirage and Darmah. The guys here reckon the forks feel good and I reckon to be using about 100mm travel on an average ride out on SA roads: I donít see why you need to have full use of the travel all the time as itís always good to have a bit extra in reserve for that extra special bump or pot hole.. :o :o

Iíll be buggered why you blokes spend so much effort in trying to set up antiquated forks, to ride like something out of the 2000ís.

This afternoon I adjusted my forks preload, dampening and rebound in 5 minutes.

Ok, they are not original, but really, if you want modern suspension, get it. Not only suspension, but my bike has 310mm disc and four spots, and instead of wobbly 38mm forks, I have 46mm jobbies.

Okay, itís not for everyone, but frankly, you are pushing shit up hill.

So once you get the front end sorted, your up to looking at the back end, once you get that sorted youíll be bracing your frame, and then ........

If I jumped of my ZX7R, and onto, letís say, a stock 1980 Jota, and tried to ride it in the same manner, Iíd end up hugging a tree, but not in a nice way.

If you want to keep it anywhere near original, settle for what you have, and enjoy it for what it is. Redax arenít blitzing the competition with 280mm brakes and 38mm Marzochi forks, why, because they have a far better alternative.

Vince, the rant is not pointed at you, but the fact that youíre post has hit 10,000+ looks, proves that there are a lot of people looking for better suspension than as 1970ís modern and superb quality ..... in itís time.



Title: Re: Harsh Cer Forks.
Post by: Legs on May 15, 2018, 09:10
Agree with Chris, why try and change a 70's bike into something equivalent to a modern bike? Cannot be done, well not without a huge amount of cash. If it hasn't got the power and handling you want, by an additional modern bike, it might work out cheaper.
Title: Re: Harsh Cer Forks.
Post by: Tippie on May 15, 2018, 09:14
Iīve got 0.90 in both of mine. I only weigh 67kg. With the emulators backed off in the street bike it now uses 100mm travel on normal riding.
This post is for people who want their original bikes updated to as good as they can get within the prettywell original framework.
Anyone could come on here and criticize all the work people do with engines and tuning and make the same comment "why donīt you just buy a modern bike". It is what we do.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 15, 2018, 09:39
I have known this bike, Pantah for at least 20 years and I used to say to the earlier owner that he should attempt to soften those horribly hard forks. Its been mine for about 10 years and a while back I decided to put my money where my mouth is. I expected to take it to a pro and spend about $400 and Bobs your uncle. It seems it wasn't that easy. I am pretty sure that pro isn't too interested in older bikes. Chris, I take your point, but finding a better set of forks from another bike integrating the wheel and brakes is about 10 years late, time to do, cost wise for me and availability. So I went the easy route or so I thought. Tippie I am twice your weight so why your springs work and mine don't is a head sctratcher, except if your Laverda twins are 25kg heavier than my Pantah.
Title: Re: Harsh Cer Forks.
Post by: Grant on May 15, 2018, 10:07
How about another pair of Pantah forks?
Sounds like yours are suss.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 15, 2018, 10:22
The last card in the deck is these new softer springs arriving tomorrow, I have the rear wheel off for a new tyre and while I was there pulled the chain guard for a blast and paint so hopefully, by next weekend I will know if I have wasted my time or not.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on May 15, 2018, 11:55
Certainly sounds like softer springs will increase your travel, Vince. I'd persevere until you feel you've done everything you can, now that you've sunk the big loot into it. Race preppers since time immemorial have been modding std stuff to get the best out of it.

Sure, you reach a point like CK and I did where you go with modern suspension, but there's a lot to be said for getting the best out of what you have. If we all abandoned ship on modding forks, noone would even bother fitting emulators, and they are tried and true.

I personally went modern because I have felt stiction ... and I hate it. One of the reasons I'll go with suspension upgrades is that I reckon the SF frame is inherently very stiff, low and in many ways resembles modern frame design. I just need ot steepen that steering head to match the modern offset triple clamps to bring trail into usable realms!! I LOVE this stuff!  :P :P :P
Title: Re: Harsh Cer Forks.
Post by: cbertozz on May 15, 2018, 13:07
Glad to see this thread still rolling 😂. Will be interesting to see how my forks behave after the bingle and the new triple clamps!

My shitty fork performance was solved by a spacer between the NZ valvy thing and the return hole! Works well at the track at least!
Title: Re: Harsh Cer Forks.
Post by: Vince on May 15, 2018, 13:12
One of my first dirt bikes was an XT 500 Yamaha, I wanted long travel suspension on it so I acquired the frontend of a later model Yamaha 2 stroke and its alloy mono-shock swingarm. I got a couple of twin shock mounts welded onto it and fitted a pair of remote reservoir Ohlins and got 11 inches at the rear. I mucked about with the other frontend, steering stem and that got me 300mm at the front but it was racked out to hell so it went to the local motolinner bloke who pulled the frame rack in as much as he could and it ended at 27 degrees from 34. That bike went great till it caught fire and burned to the ground. So this isn't new to me.
Title: Re: Harsh Cer Forks.
Post by: Legs on May 15, 2018, 23:17
Quote
This post is for people who want their original bikes updated to as good as they can get within the prettywell original framework.
Anyone could come on here and criticize all the work people do with engines and tuning and make the same comment "why donīt you just buy a modern bike". It is what we do.
Get off your high horse Tippie. It wasn't a go at people on the forum, just stating a different point of view. I personally believe that updating a bike is fine, emulators, shocks, ignition, tyres etc., done it myself but I reckon there is a limit to how much a bike should be changed from how it left the factory. On the other hand I am amazed by the lengths some take to keep their bike(s) totally original.
I'm of the opinion that modifications should be limited to keep them safe and reliable and that any other changes should be changes that would have been done back in the day.
Just an opinion ;)
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on May 16, 2018, 00:59
Just an opinion ;)
High horse? I think Tippie's was also just an opinion ... just sayin'  ;D
Title: Re: Harsh Cer Forks.
Post by: Legs on May 16, 2018, 01:51
Quite right, apologies.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 16, 2018, 03:24
I doubt that lower rate springs will increase fork travel by much. The distance that the wheel moves up and down over bumps is determined as much (if not more) by the shape of the bumps and the fork damping as it is by the spring rate.

Best way to get more suspension travel is to find a bumpier road and ride faster!   :D
Title: Re: Harsh Cer Forks.
Post by: chrisk on May 16, 2018, 04:11
How about another pair of Pantah forks?
Sounds like yours are suss.

I think Grant has made the most valid point yet.
Title: Re: Harsh Cer Forks.
Post by: AndyW on May 18, 2018, 08:13
How far back or up do you sit on your Pantah Vince? i.e. are they std handlebars or more upright (and with risers perhaps?)? could be you don't have enough weight over the front wheel to make the suspension work properly: another reason to of for softer springs...
Title: Re: Harsh Cer Forks.
Post by: Vince on May 18, 2018, 08:19
That makes sense, I have modified the seat by removing the front bit of the removable pillion section so I can fit a bit better and have clipons with risers up as high as I can get them. That would affect the bikes front-back balance but it still has these solid at 80mm forks. The new springs haven't arrived as yet, I am sweating on them making a big difference.
Title: Re: Harsh Cer Forks.
Post by: AndyW on May 18, 2018, 08:30
Progressives might be the way to go too...
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 19, 2018, 01:35
Take the springs out and pump them up with air to about 200psi ;)
Title: Re: Harsh Cer Forks.
Post by: Vince on May 19, 2018, 03:54
I am heavy, maybe 300psi. The pain continues, I discovered why this Pantah seems to have no top end power, someone reduced the rear sprocket from a 40 to a 38. I had ordered a rear tyre and wanted to paint the chain guard so when the tyre arrived I was going to do the sprocket swop, I ordered one and it arrived the next morning, then it I almost broke my alan key and my 12-volt rattle gun wouldn't touch the sprocket bolts. I had to visit a mate to pull it and even then it took a 3/4 drive air rattle gun to loses them. So all really to fit the wheel and I notice the bike shop has fitted the tyre backwards. I told them what side the chain was on as well. So hopefully Monday the softer fork springs will arrive and the tyre will be reversed and the bike might turn a wheel and I will finally know whether the missing 50mm of fork travel has come back.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on May 19, 2018, 05:37
The pain continues, I discovered why this Pantah seems to have no top end power, someone reduced the rear sprocket from a 40 to a 38.
Hate to rain on your party, Vince, but the gearing might affect top end in high gears, but if it won't produce power at revs in any gear it's nothing to do with the gearing! I fitted a one tooth bigger gearbox sprocket to that little 250 I rode to Sydney last year - still flies at revs in every gear, just a bit sluggish in 6th up a hill (below 8,000rpm!)
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 19, 2018, 05:45
Telling them what side the chain is on is expecting them to work out the rotation direction themselves. Seems to be beyond some of the tyre fitters to do that. ::)

When I take a wheel to a shop to have a tyre fitted, I always grab a felt tip pen and put arrows on the rim showing the direction of rotation, so it eliminates that step in their thought process. All they have to do is match the arrows on the rim with the arrow on the tyre. They couldn't possibly fuck that up, could they? 

Well, yes. They could fuck it up. Even with the arrows on the rim, it pays to check before leaving the shop. On one occasion I went to pick up a wheel from a shop, and the tyre arse about. I told bloke behind the counter. He called the mechanic over, and the mechanic called the guy who actually fitted the tyre. He looked about 16 years old, and had just started work there a couple of days before. It wasn't his fault though. They'd shown how to operate the tyre changing machine but forgot to tell him that tyres had a direction arrow on them! The kid said he thought I'd put arrows on the rim so I knew which way to put it back on the bike.

He'd done about 8 tyres since they put him on that job. The probability is that 50% of them would have been arse about.  I suggested that they call those customers and ask them to check the arrows on their tyres, but I dunno if they ever did. 
Title: Re: Harsh Cer Forks.
Post by: Vince on May 19, 2018, 05:55
Yes, I get that, it was geared to the moon though. It took a fair bit of clutch slip to get off the lights and with a cold engine that was a pain in the arse. The top end effect was flat accelerating above 5k and a bigger gap between gears. There was a discussion on the Pantah Face Fuck page on gearing that worked and what I had,
15 x38 was too tall by all accounts. It's now 15 x40, not a major change but it's only a 600 and I hope this will work to the engines strengths. Doesn't help I am 125kgs as well. The tyre fitter was the shop's OWNER, and he is who I told about the chain side. I have known him for 30 years, okish bloke even if he still tries to sell me bikes I dont want all the time.
Title: Re: Harsh Cer Forks.
Post by: helicopterjim on May 19, 2018, 07:33
Telling them what side the chain is on is expecting them to work out the rotation direction themselves. Seems to be beyond some of the tyre fitters to do that. ::)

I have my own tire machine ...... and I have messed up on at least one occasion. Thankfully ..... having my own tire machine means I can fix my own fuckup.

I'm pretty sure it was one of those look at the tire ..... yep that's the right way ....... lube the tire with soap ..... then flip it over and lube the other side. Number one way to mess up tire install.

Once you do it once ...... you won't do it again. Sorry for the kid who didn't get trained properly. Hoping he turns out to be one of the ones who's a thinker.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on May 19, 2018, 12:53
I have my own tire machine ......
So you obviously know about the dot that indicates where the valve aligns (to aid balancing), Jim?

Bicycle tyres are nearly all directional these days as well. I know correct fitment from tread patterns without trying to find the arrow these days.

Vince, once you get your 120mm of travel (keep 10mm for emergencies  ;D , give it to a dyno person. You just might find a whole shedload of missing power!
Title: Re: Harsh Cer Forks.
Post by: helicopterjim on May 19, 2018, 15:36
So you obviously know about the dot that indicates where the valve aligns (to aid balancing), Jim?


Yes ....... and don't trust it to be the best spot to allow the best balancing.  I have had a couple of tires that balanced better with the dot 180 degrees out. I have also checked the balance of the bare rim and found some to be perfect and some quite unbalanced ......... most likely a spoked wheel in the latter case.
Title: Re: Harsh Cer Forks.
Post by: chrisk on May 20, 2018, 07:42
John took me on, almost unquestionably, Australiaís roughest sealed road. Proved two things, my front forks are way too harsh a, are the rear shocks.

Great on the track, and even the two front wheel lockupís didnít unsettle it too much.

So, Iím going lighter fork oil for a start and see what happens then.
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 20, 2018, 08:06
John took me on, almost unquestionably, Australiaís roughest sealed road. Proved two things, my front forks are way too harsh a, are the rear shocks.

Great on the track, and even the two front wheel lockupís didnít unsettle it too much.

So, Iím going lighter fork oil for a start and see what happens then.
Lighter than what w ?
Title: Re: Harsh Cer Forks.
Post by: chrisk on May 20, 2018, 08:34
My own mixture Dave, 1 part 10w and half part 15w
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 20, 2018, 09:49
Stick with the 10w and stick on the goat tracks....remove the falsies and pin it  ;) only place coppers don't hang out  8)

Makes ya feel alive a little bit of front brake lock up and jarring thru the bones  ;D
Title: Re: Harsh Cer Forks.
Post by: Vince on May 20, 2018, 11:26
Chris, does your fork have clickers. What helps a lot with the rear shocks is pulling the bump stops down and seeing what the sag is and how much travel you are using. Without knowing this its imposable to adjust the shock settings, it could be soft and bottoming or so hard it's not moving much. Same with the forks, cable tie time.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 21, 2018, 02:58
After politely wanting 3 and a half days for the fork springs to come from across Sydney I gave them a ring only to find they had forgotten to send them. Fuck me.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 21, 2018, 04:36
I love my Laverda, on it, you can remove and replace the rear wheel while leaving the chain untouched. Its hard to believe but I had to break the chain on the Pantah to refit the wheel now with a slightly bigger rear sprocket, bloody stupid design. Bloody chain lube is like tar, Andy was right, the less lube the better.
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 21, 2018, 07:22
Now Now Vince..... nothin wrong with a bit of chainlube now n then  ;) after a ride and wipe off excess.

If yours has turned to tar.... maybe ya need to clean it more often (rag soaked in Inox/wd40)

Give it some lovin and it will pay ya back in spades   ;)
Title: Re: Harsh Cer Forks.
Post by: Vince on May 23, 2018, 04:33
I finally received the lighter fork springs, before 0.95 and now 0.8. With the same, tiny amount of preload, I now have 100mm of travel with 40mm of sag. That's with a brand new tyre, zero ks, so I wasn't pushing it. Its much better, but I need to get beyond my block and at higher speeds. It needs a bit more preload to get to a better 30mm sag figure. I am very glad I didnt go to 0.85 spring, thanks for the calcs, Cam. Cam calculated there would only be a 5mm difference in travel between the 0.8 and 0.85 springs, that's theoretical as real-world stuff has an effect.
The gearing change looks very good as well.
Title: Re: Harsh Cer Forks.
Post by: Davo on May 23, 2018, 10:08
In theory, reality and theory are the same but in reality they are different.  ::)
Title: Re: Harsh Cer Forks.
Post by: Vince on May 23, 2018, 10:11
In the building game there are drawing dimensions and site dimensions, there NEVER the same.
Title: Re: Harsh Cer Forks.
Post by: AndyW on May 23, 2018, 11:07
I finally received the lighter fork springs, before 0.95 and now 0.8. With the same, tiny amount of preload, I now have 100mm of travel with 40mm of sag. That's with a brand new tyre, zero ks, so I wasn't pushing it. Its much better, but I need to get beyond my block and at higher speeds. It needs a bit more preload to get to a better 30mm sag figure. I am very glad I didnt go to 0.85 spring, thanks for the calcs, Cam. Cam calculated there would only be a 5mm difference in travel between the 0.8 and 0.85 springs, that's theoretical as real-world stuff has an effect.
The gearing change looks very good as well.

I hope they're not too soft that you start wallowing around... :o :o ;D
Title: Re: Harsh Cer Forks.
Post by: Vince on May 23, 2018, 11:10
Me too, but from that short test its still far from wallowing. I am adding 5mm of washers to see if I can get closer to 30mm of sag
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on May 24, 2018, 01:11
Good work, Vince. Sounds like you're getting close to sorted. And hopefully many will benefit from your time and money expended in the process   :P
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 24, 2018, 01:48
In theory, reality and theory are the same but in reality they are different.  ::)

If theory and reality are different, there's something wrong with the theory.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2018, 02:17
Butterfly effect, tiny random inputs that result in big unexpected changes. And that's 90% of the fun playing with this. Do something that's taken as gospel and see for yourself. And that's my biggest lesson with this, you're going to need 0.95 springs as your a big boy and that's what works for the GSXRs and stuff I normally do. O your only getting 80mm of travel, start coming up with lots of expensive fixes. No, lest not try softer springs as that's imposable to be the fix. Its a 5 minutes experiment, NO that cannot be it. Have you tried other springs on other old bikes, NO but that cannot be it. It's not been that expensive, $180 for the second set of springs, $120 for the hard anodising, $300 for the expert to pull them down for the second time and find and do nothing, that pissed me off. And $100 for assorted oil and stuff plus hours of fun. It least I finally got somewhere,thankfully
Title: Re: Harsh Cer Forks.
Post by: Grant on May 24, 2018, 05:31
If theory and reality are different, there's something wrong with the theory.

Or reality!  ???

Could be a glitch in the matrix.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2018, 06:12
Here is the latest glitch, I am doing a gearing change so while I am at it a new chain seemed smart. Off I go across Sydney to the National Distributor, well no we dont have any here. So its coming from Melbourne, chain arrives and I attempt top fit it. No removable chain clip, only a rivotable one and I am not keen. Luckily I bought 2 removable clips for the Laverda while I was there, but there also 530 but a grade stronger and don't fit. So I ring them and it seems I was sent an X ring chain and not an O ring, nobody have any removable clips but he can send me an O ring chain with a removable clip from Melbourne for free as its there stuff up but I won't get it till Monday. How does anybody make any money these days?
Title: Re: Harsh Cer Forks.
Post by: helicopterjim on May 24, 2018, 06:18
so while I am at it a new chain seemed smart.

Smart phones, smart cars ....... now smart chains?

I have a brand new dumb chain ........ no X's,Y's or Z's ........... I don't think it even has any abc's ....... dumb as a chain can be.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2018, 06:24
What did piss me off other than no bike again for the weekend is its a horribly dirty job I was expecting to do once and clean up, now to do it all again 4 days later.
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 24, 2018, 06:43
Run over any chinaman lately Vince ?  ::)
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2018, 06:46
Maybe
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 24, 2018, 07:26
Blimey. You'd think 530 o-ring chains would be available at any half-decent bike shop. I'm sure I could pick one up here in Hobart without much trouble.  I guess you have to expect problems when you live in a back-water hic town like Sydney  ;)
Title: Re: Harsh Cer Forks.
Post by: Davo on May 24, 2018, 08:13
Have you tried somewhere like Motorcycle Accessories Supermarket? 
Title: Re: Harsh Cer Forks.
Post by: Shajota on May 24, 2018, 08:36
Why don't you just use the rivet connector ???
Sounds like you're going to get a free one to have as a spare anyway................
(surely there's heaps of bike shops in Sydney that have chains :o :o)
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2018, 08:50
I was heading in the general direction of Tsubaki Chains Australia head office and I have bought from them with zero issues before, I didn't even ring to see if they had stock as its a huge warehouse. I am a creature of habit so that's what I did. I could probably rivot the chain but I haven't done it before, and having the ability to easily remove the chain seems like a good idea. No rides this weekend so not a big issue. At least I finally could move the bike so the mower could come out of the tiny shed. The grass was waist high and now a bit shorter.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on May 24, 2018, 12:45
Tsubaki would be TK chain? Wonder where they are in Melbourne?

I'm thinking of going the riveting machine option when I fit my project bikes with chains. But I do like being able to break them to make removing my non-Laverda wheels easier.
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 24, 2018, 13:28
Manufacturers going away from joining clips nowa days as to many knob heads place the clip the wrong way rnd   ::)

Riveting and breaking a riveted chain is a piece a piss..... with the right tool (who wooda thought)  and just as easy to install new joining link with said tool  ;)

Get with it you blokes and tool up   8)
Title: Re: Harsh Cer Forks.
Post by: Vince on May 24, 2018, 15:19
My chain breaker wouldn't touch this chain, I had to grind the rivet heads off to get it to length. The pinheads were peaned over one hell of a lot, the breaker pushed them out fine after the grinder did its thing. This was there lower strength 530 O ring, or was supposed to be as they sent there X ring. I have there top of the range chromed 530 O ring on my 3C. The Pantah one takes 120hp so its fine, the top rated one will take Bussa power so its fine on the 3C.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 25, 2018, 02:19
Get with it you blokes and tool up   8)

I've only ever used a hammer and punch against a heavy dolly on those rivet type chains. Also use an angle grinder on the pins to break them as Vince described.

I thought my methods were a bit rough until I was at the Stafford Bike show some years ago and bought a primary chain from Andy the chain man.  He cut the number of links I needed off his length of stock with a grinder, put in a connecting link and peened it over with a hammer and punch!
Title: Re: Harsh Cer Forks.
Post by: Vince on May 25, 2018, 04:04
Wheres a Blacksmith when you need one, my welder will love this. After the Lawton Bushman sidestand was so great on my 3C I decided the Pantah needed one as I was sick of the ballet dance getting off had become. According to common knowledge, a Cagiva Alazzurra being all but a Pantah would fit easily, not on mine. After 2 nightmare days it finally was on but took plenty of bending to work. But its far from easy, the toe lever sits behind the centrestand lever and they both get in the way of each other. So the sidestand toe lever got cut off today and I need to make a new one 8mm solid and curved around the muffler. Clearance for the curved bit is 80mm diameter. I expect if the solid bar gets welded to an 80mm steel pipe one end and heated to cherry red it will bend around to the curve I want.
Nowhere near as easy at the Laverda one as I said.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 25, 2018, 05:21
I put a Kawasaki side stand on my MHR Ducati. I made up a little plate for the stand to bolt onto. It fixes to the frame plate that holds the centre stand pivot and is held in place by the centre stand bolt and another bolt through a hole drilled in the frame plate. Works perfectly and tucks away neatly when folded.

I could have made the mounting plate bigger so it picks up the lower rear engine mount bolt (rather than drill a hole in the frame plate) but the rusty old piece of 8mm scrap steel plate I had lying around wasn't big enough. I'm not such a stickler for originality that drilling a hole in my bike bothered me anyway. If it bothers the next owner, he can weld the hole up again.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 25, 2018, 05:22
Finished MHR stand installation
Title: Re: Harsh Cer Forks.
Post by: Vince on May 25, 2018, 05:42
Mine was supposed to bolt straight on, nobody said the whole exhaust, centre stand and bottom engine mount bolt needed to come off before it would fit. It was a big job.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 25, 2018, 09:50
Replacement chain arrived today from Perth, a week for the fork springs to come 50ks. One day for 4000ks from Perth for the chain
Title: Re: Harsh Cer Forks.
Post by: SimonR501 on May 25, 2018, 15:34
Replacement chain arrived today from Perth, a week for the fork springs to come 50ks. One day for 4000ks from Perth for the chain
Who said WA stood for 'wait a while'?
Title: Re: Harsh Cer Forks.
Post by: Vince on May 26, 2018, 03:15
They sent me, wait for it EXACTLY THE SAME CHAIN.So I now have just riveted my first X ring chain. The only hard bit was I didnt have a small enough G cramp to press the plate on the pins. All done now, hope I have peened it enough.
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 26, 2018, 03:55
Ffs Vince go down ya local bike shop and lash out on the right tool ! Breaker and re peener.  No clamps needed and no need to get out the hammer n punch that you retired years ago   ;)
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 26, 2018, 03:57
Could be ugly  :o if ya haven't penned those pegs over enough.

 :-X :-X
Title: Re: Harsh Cer Forks.
Post by: Vince on May 26, 2018, 04:02
I had my brother hold a 2 1/2 pound lump hammer behind the link and had at it with a good size pin punch so I expect its ok. We will see.
Title: Re: Harsh Cer Forks.
Post by: chrisk on May 26, 2018, 04:05
I had my brother hold a 2 1/2 pound lump hammer behind the link and had at it with a good size pin punch so I expect its ok. We will see.

Doesnít need much Vince, you came in Hooksey, line and sinker.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on May 26, 2018, 04:43
Could be ugly  :o if ya haven't penned those pegs over enough.

I prefer to peen them, using a pen doesn't usually achieve the desired outcome. Especially if it's a felt tip pen.
Title: Re: Harsh Cer Forks.
Post by: chrisk on May 26, 2018, 04:59
If using a pen, to do the joining link, you best be doing it on a Jota  :P

Title: Re: Harsh Cer Forks.
Post by: Shajota on May 26, 2018, 05:06
Yeh, really doesn't need much to keep the side plate on the straight and narrow. Even seen a few bikes that have had the clip link missing (for who knows how long) and plates haven't ejected themselves off, so can't be much sideways pressure........................
Title: Re: Harsh Cer Forks.
Post by: breganzane on May 26, 2018, 05:51
I have done them with a lump hammer and something heavy behind at first, then not having any money I made myself up a thing like a small very strong g-clamp with a cup to press the sideplate and a point that splayed out the rivets, which worked quite well.  Somewhat later I got a proper tool and discovered how easy the system is with the right gear.  The side plate is a press fit, and there's a set distance it should go on to get the right compression on the o/x-rings.  Doing it manually that distance can be done wrong, whereas the tool sets it correctly in one go and you can't over-press it.
The DID tool has 3 setups, first to push out a pin to shorten or split the chain, a second to press the side plate on to the correct width, and a third to peen out the hollow rivet.  I never had a chain failure with any of the methods but the correct tool makes it a lot easier and sets things just-so.
The forces can be pretty high, I would advise against buying a chinese crap tool, their steels never seem to be good enough for such things.  The DID is not cheap (~$200) but will last your whole life.  There are probably decent ones out of Taiwan if it's sold by someone reputable (brand Bikeservice makes some nice stuff, COO Taiwan mostly).  But by then you're pretty much at the price of the DID anyhow.
Vince - you hijacked your own thread!  If you want my home made rivetter let me know.  It does not shorten the chain, I used to angle grind the heads off and punch the pins out which is a PITA.
Title: Re: Harsh Cer Forks.
Post by: Vince on May 26, 2018, 06:16
I have an old Renals tool, it pushes but nothing else. I googled rivoting a link and watch a couple of vids, done correctly as Steve said its a lot more technical than you would think. I made sure the link could still pivot reasonably smoothly, it still pisses me off a simple clip link seems so hard to get for THAT chain that I bought.
Title: Re: Harsh Cer Forks.
Post by: Cosi on May 26, 2018, 08:36
Obviously the right tool is the best way to go , once you buy one you wonder why the fuck you. Bothherd with lump hammers etc, but if your that way inclined to get the plate seated square all you need is two 8 mm ring spanners and clamp to wind it on, then bash away with your hammers and punch
Title: Re: Harsh Cer Forks.
Post by: hooksey on May 26, 2018, 09:02
Hellooooo Helloooooo  (announce)

The Tigers won............ and nobody gives a fuck about ya chain any more Vince because, you no listen. (dunno)

I will spell it out for ya......... "Get a tool for the chain link" and you will be able to spend more time faffin around with ya front forks  (bolt)
Title: Re: Harsh Cer Forks.
Post by: Davo on May 26, 2018, 09:06
Peter Stevens sell a DID lookalike for $99. Same as what I use and works well. Always grind the tops off the rivets before pushing them out to save the pin but. https://www.peterstevens.com.au/heavy-duty-chain-breaker-riveter.html
Title: Re: Harsh Cer Forks.
Post by: Vince on October 15, 2018, 00:39
Last ride I was at it again on the Cer forked 3C.I wanted a softer ride on square edged  bumps as on a long day I would hit at least 3 or 4 bumps that would give a huge kick to the forks.My really old emulators came with 1 high speed compression hole. The later ones come with 2 holes and they are more compliant, in the attempted fixes on my Maz forked Pantah the US based Race Tech vintage expert Matt suggested I go the whole hog and try 4 holes.And I did, but I had gone to soft with the emulator spring preload ,at 2 turns and with the Pantahs catastrophic engine failure its been sidelined for a while.So before the last Laverda ride I pulled the emulators and drilled a 3rd hole in the high speed compression plate. One problem is the bike now runs a different front tyre is that's a variable in the mix. It had a T31 Bridgestone sports touring tyre and now its got a BT016 full blown sports tyre, both are Radials and both had the same pressures at 37psi.So we did thew full Putty Rd loop and to me its helped a lot. The bike has a much more planted feel, especially in those long fast rough as guts sweepers out near Jerries cafe. The bike was a bit loose before,nervous and kicking about.It feels much more planted.Where its the tyre or the extra hole I am not sure. I was 100% going to go to 4 holes after this but not till after the Snowy Run.What got me back to doing this was doing a day on Doug Homes old bike now owned by Marty. It had the best fork action I have tried yet. Compliant and firm, mine hopefully will be similar soon.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on October 15, 2018, 12:26
Sounds like you need to replicate those forks on Marty's bike, Vince!
Title: Re: Harsh Cer Forks.
Post by: Vince on October 15, 2018, 14:22
Yep, I missed my opportunity when he did the fork seals
Title: Re: Harsh Cer Forks.
Post by: Tippie on October 15, 2018, 17:32
Swap the forks when heīs not looking!
Title: Re: Harsh Cer Forks.
Post by: Vince on October 15, 2018, 23:32
Good idea,no wait he is too big to do this too.Just to clarify,I could grit my teeth,hold the tank tight with my knees,and power through all this without much effort but it's fun to see what happens when I change something relatively easy to do. I have a mate who is elbow deep in shim changes in Cartridge forks on a KTM big twin, that's way beyond my comfort zone. So is most other high tech changes some do here, Quinton's and Tippies stuff for interest.I was surprised how little info there is out there on the stuff you can adjust on Emulators and its fun to see what effects it has.And the horrible fork issues I was having with the same fork on my Pantah and used on lots of Laverdas,now that fork is 100% better
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on October 16, 2018, 02:10
A while back I rebuilt a pair of 38mm Ceriani forks and sold them to Maurice. He now has them on a bike and says they work really well. He reckons they're much better than an identical pair of forks on one of his other bikes. They had nothing fancy like emulators in them, just the basic old Ceriani damper rods. The only "custom" thing I did was to polish the insides of the fork stanchions and machine up new pistons for them with only a couple of thou clearance. I only did that because the old cast alloy pistons had expanded and were tight. I could have just turned them down to size but one of them I had to drive out with a hammer and drift, and it was fucked by the time it came out.  I figured if I was making one piston, I may as well make two. There was a slight difference in bore diameter of each fork leg. It was only a few thou, but I made the piston clearances so close that larger piston wouldn't fit in the smaller bore.

Anyway, perhaps the secret to getting Cerianis to work well is to set them up with polished piston bores and nice billet pistons with minimal clearance. 

BTW, the internal polishing was done by spinning the stanchion in the lathe chuck while shoving a broom handle in and out about a million times with various types of polishing contraptions on the end of it. Starting with emery paper, then steel wool, kitchen scouring pad and finally a soft mop with polishing soap.  Kept it up until the insides were nice and shiny (they were a bit dull and rough looking to start with). Seems it may have been worth the effort. 
Title: Re: Harsh Cer Forks.
Post by: Vince on October 16, 2018, 02:32
I keep getting told by an unnamed individual that his bike forks are fine std.My Laverda forks were ok but what really got me going was the Horrible Maz forks in the Pantah,std they were virtually rigid, and after doing the usual upgrades for considerable cash they were just as shit.The cer tripals are not as offset as the Maz and what I think is with this laid out setup causing plenty of friction, add way to stiff a set of fork springs and you get a really stiff fork action.Any info on improvements is helpful,especially cheap ones.
Title: Re: Harsh Cer Forks.
Post by: Davo on October 16, 2018, 03:04
I remember my standard Ceriani forks as being just fine and am sorry that I ever read the section on "improvement" on Laverdamania. The only reason I started was because a) I read that section (by Doug Home) & b) same as Cam I had a seized piston that needed to be belted out so the forks were apart anyway.

Now, after converting to Racetech emulators and ending up with forks that were worse than before I find that Racetech have decided that there needs to be an adaptor to force all oil through the emulator and this demands the use of Racetech springs as the Ceriani springs are now way too long and the preload is through the roof.

I say, leave well enough alone and stick with standard. Or if you are that pernickety about suspension do a conversion and put in complete new forks and triple clamps.
Title: Re: Harsh Cer Forks.
Post by: maurice turner on October 16, 2018, 11:24
A while back I rebuilt a pair of 38mm Ceriani forks and sold them to Maurice. He now has them on a bike and says they work really well. He reckons they're much better than an identical pair of forks on one of his other bikes. They had nothing fancy like emulators in them, just the basic old Ceriani damper rods. The only "custom" thing I did was to polish the insides of the fork stanchions and machine up new pistons for them with only a couple of thou clearance. I only did that because the old cast alloy pistons had expanded and were tight. I could have just turned them down to size but one of them I had to drive out with a hammer and drift, and it was fucked by the time it came out.  I figured if I was making one piston, I may as well make two. There was a slight difference in bore diameter of each fork leg. It was only a few thou, but I made the piston clearances so close that larger piston wouldn't fit in the smaller bore.

Anyway, perhaps the secret to getting Cerianis to work well is to set them up with polished piston bores and nice billet pistons with minimal clearance. 

BTW, the internal polishing was done by spinning the stanchion in the lathe chuck while shoving a broom handle in and out about a million times with various types of polishing contraptions on the end of it. Starting with emery paper, then steel wool, kitchen scouring pad and finally a soft mop with polishing soap.  Kept it up until the insides were nice and shiny (they were a bit dull and rough looking to start with). Seems it may have been worth the effort.
And quite right is Cam these forks are fantastic they are progressive and compliant and perfect for what they are I would never try and transform a pair of 1970s forks into a modern equivalent.
You would be better off buying a monster like Terry has done Vince.
Title: Re: Harsh Cer Forks.
Post by: Vince on October 16, 2018, 14:13
The first set of Emulators I fitted must be 20 years ago. I needed a better brake on my Husky 420cc 2 stroke Automatic enduro bike,that's with syntrivacaly operated  4 speed gearbox that changes by itself and its as fast as it sounds even now. Close the throttle on it going down a big hill and they have ZERO engine braking.It disengages the centrifugal clutches and freewheels. So I fitted a KX 125 43mm disc brake fork,great at big jumps completely crap on braking bumps. After fitting the $140 Emulators it was 100% better all round zero adjustments.Smooth as butter. So we have $170,cost now, for Emulators against 6 or 7 thousand Dollars and more for a Monster.Gee not sure that makes any sense at all but thanks for the unhelpful tip.
Title: Re: Harsh Cer Forks.
Post by: Grant on October 16, 2018, 14:30
I wouldn't compare the fork control requirements on a dirt bike with those of a heavy road bike.
Apples and oranges.
Title: Re: Harsh Cer Forks.
Post by: Vince on October 16, 2018, 18:54
They are exactly the same,the only difference is the size of the suspension movements,bigger by proportion of bump size over suspension travel, or the speed of travel generated.Those gradual dips or sudden dips,the latter are the hardest to absorb,requiring a fast response from the fork,that's what I have been trying to take out with the extra high speed compression damping holes.That's what convinced me how effective Emulators can be.The whole point is making the fork work on a much wider scale of response,from wacking big potholes to braking bumps or corrugations caused by trucks braking into corners,or expansion joints on bridges.As many different bumps as I can find.What's hard is to much damping and not enough damping can feel the same,especially on road bikes with much less travel.I have a test track for these square edged bumps, across the CBD of Sydney is an expressway over a train track over a ferry terminal called The Carl Expressway over Circular Key. This has huge expansion joints that give a huge jolt to the bike and that has lessened considerably with each 7/64th of an inch I have drilled.Yes it's shocking to see an actual scientific test of what I am doing.All this time wasted on trying to make a fork more modern.My time, my fork.Keeps my mind active and hopefully improves the way the bike goes.
Title: Re: Harsh Cer Forks.
Post by: Grant on October 16, 2018, 19:05
Have to disagree, but each to his own.
Range of movement, sprung load, forces endured etc.
Title: Re: Harsh Cer Forks.
Post by: Laverda SF on October 16, 2018, 19:24
Ever been with a bunch of Cruisers waddling along at about 50 to 70km on a back line for about 50 clicks. I stood on the pegs keeping my ass from throwing me off the bike and my spine hurt. Would sooner have barrelled at about 90 to 100 clicks with Ceriani's but you would have to dodge Deer, Bears, Ground Hogs and Live Stock... etc - Risky. All the Cruiser Riders set straight up and gabbing in comfort.

I couldn't wait for smooth asphalt, hills and corners to be in Breganzie / Ceriani Territory - Priority of the Laverda Sport Bike and Race.

The triple tree of my SF never shaked with Ceriani's. All you needed was the form and the balls the roll the bike over in Hi-Speed Corners. And you never got enough practice ;o)

Title: Re: Harsh Cer Forks.
Post by: Cosi on October 16, 2018, 19:52
Apples and oranges.
Iíve heard if you mix them together it make a lovely juice
Title: Re: Harsh Cer Forks.
Post by: chrisk on October 16, 2018, 22:00
The oranges and apples variation isnít that great Grant.

In both cases the main objective is to keep the front wheel on the ground as much as possible, over various surface conditions.

Dampening, and rebound are adjusted to suit riders weight and basic riding position, whilst still being compliant.

Sure, the oranges have longer travel, but the basics of the fork operation are very similar to apples.

I rode my 78 DT400 2000klm on some of the worst corrugated roads in Australia, if I did this trip on my WR the trip would have been so much easier.

Frankly, I doubt very much that anyone could doctor the DT forks to react the same as the WR.

Unlike Vince, I couldnít be bothered trying to make the standard Laverda toothpick type forks ride like a modern bike.... easier to change to something that works much better, from the get go.

Once Vince gets his forks sorted, to his liking, I doubt heíd never consider swapping them onto a Pannigale, because they work so well. Extreme example, but you know what Iím getting at.

Title: Re: Harsh Cer Forks.
Post by: Vince on October 16, 2018, 23:08
I get fluid dynamics is complicated, get that velocity squared stuff but I am not doing the maths.All I am doing is drilling a hole as going for a ride.Or changing fork weight or height and again going for a ride.The bloody reason why this has taken so long is in both cases,Cer on the Laverda had way to hard Emulator springs when I bought it and one only High Speed compression hole.And the Maz forks on the Pantah came new with way to stiff major fork springs and  the suspension guru recommended and sold me way to stiff replacements. In both cases I spent years changing stuff with zero effects that I needed.They need to be close to correct for these adjustments that I have tried to affect them.If either of these things were correct when I first did these jobs I probably would have left them where they were. But both were supplied by the local suspension juro who does great work on modern bikes but far from that on old bikes.At no point did he suggest changing anything after follow up visits.I got 100% more info and much better advice from the Race Tech vintage bike bloke in the USA,Matt who clued me in on what was wrong in the basic fit up.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on October 16, 2018, 23:44
Good on you Vince. It is fun and engaging to play with improving something - why else would we fit flat slide carbies, Jota cams and myriad other mods to our old bikes. What Cam did to his Ceris is a perfect example of improving something from stock.

When i ran 18s on my SF with 35mm Ceris and drum that later served for twin Brembos it behaved incredibly well on bumpy roads. Eventually fitted Marzocchi M1Rs but they were so poorly set up that it was a retrograde step. Troubles really started when I went to 17s (which increased tyre choices by about 5-fold) - then you get into incompatible steering geometry (rake and trail are all wrong).

Going with modern, cartridge type forks was a big improvement (as Chris K did), but again, the geometry on a frame with around 29 deg of rake and shallow offset triple clamps meant it was never quite right. Nothing dire, it still rode well on public roads of all kinds and was fine to ride at the Island, save the cornering clearance issues.  ... so the final stage is where I'm at now, redesigning the geometry. It might turn out to be a nightmare, but it might make me smile widely. Either way, I have bike #2 as the more stock fallback option.

At the end of the day it's all part of a personal journey.
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on October 17, 2018, 00:12
I've also fitted damper valves to a couple of my Marzocchi forked bikes (Jota and Ducati MHR). I think the fork action was improved, but my arse isn't particularly sensitive to bumps so I'm not really sure. Maybe I need Vince to bring his calibrated arse to Tassie to evaluate the suspension on my bikes  ;D
Title: Re: Harsh Cer Forks.
Post by: Chris M. on October 17, 2018, 00:42
Vince I love your determination but ChrisK hit the nail on the head when he said;"I couldnít be bothered trying to make the standard Laverda toothpick type forks ride like a modern bike.... easier to change to something that works much better, from the get go."

But ...... I'm as bad as you are, installing teflon bushes into my 38mm Marzocchi forks.

I'm afraid there is no technology available that you haven't already tried that will fix your forks. The Japs discovered this in the early 80's so they introduced bushed forks which set the standard for mass produced suspension. You cannot improve your forks with out reducing sticktion.

There is a solution to all this and that's to just buy a brand new set of forks from Canada that already have teflon bushes and Maxton cartridges or buy some 38mm Cerianis with adjustable compression/preload from Hungary. No idea of the cost of the EN Products ones and I'd expect it's horrific but the Hungarian ones cost under 2 grand.

http://www.e-nproducts.com/products.php

http://www.e-nproducts.com/products.php
Title: Re: Harsh Cer Forks.
Post by: Vince on October 17, 2018, 00:58
My memory of Tassie is you dont have bumps, even the dirt was pretty smooth.Hi Chris,your bush comments are true and if your really looking at major improvements that's needed.But by then your into fork flex territory.That Kawasaki fork I fitted to that Husky replaced the std 35mm fork with 43mm ones and a much better brake. Even with the weedy drum brake on the Husky you could feel the forks bending,majorly better with the 43mm ones. Years before I did that Husky stuff I fitted some latter Yamaha forks to an XT 500 with the alloy single shock swingarm converted to twin shocks to get more suspension travel. That bit worked great but it ended up with about 150mm of trail so I got the local frame bloke to push it closer to 90mm on his Motoliner.
That was a great success,till it caught fire and burned to a crisp a few years later.Sometime around then I fitted a Ducati Parallel twin Maz disc brake frontend to my 64 Bonnie,that also worked great. So I have been doing this stuff for a while.
Title: Re: Harsh Cer Forks.
Post by: AndyW on October 17, 2018, 04:00
I fitted some latter Yamaha forks to an XT 500 with the alloy single shock swingarm converted to twin shocks to get more suspension travel.
A mono-shock  T500? That would be a rare beast indeed Vince, are you sure you donít mean that the other way around?
Title: Re: Harsh Cer Forks.
Post by: Vince on October 17, 2018, 04:30
I bought the whole rolling chassis off a later model 250 Yamaha 2 stroke, it was a single shock bike so I got some alloy welding done for twin shocks and fitted some piggyback Husky shocks I had acquired. So that was an XT 500 with 280mm of suspension travel,better than the 100mm it came with.The fire happened because the XT tank had vertical fuel taps and if you put it on the ground it would take a core sample of dirt that would end up in the needle and seat. Discovered that after the fire.
There was 10 blokes on that ride and when the fire started all 10 tried to bury the bike in the soft dirt it was on.Zero chance of putting it out,the fuel in the tank ended up boiling off and the cap was like an Oxi torch. Sad end to a great bike. BTW you should have seen how hard I was watching those swingarm shock mounts at first, just a bit scary doing small jumps at first. It was fine, no bending or cracking. I was a bit more crazy back then.Fun job to do



Title: Re: Harsh Cer Forks.
Post by: Vince on November 13, 2018, 20:27
I was pretty happy with the forks on The Snowy Ride,there are 2 more things I want to try but not at the moment. The shocks, Icons are something that needs work. We did a shocker, get it of a road called The Olympic Way, in my case it felt like someone was lining up and kicking me square up the arse ever second. Bang Bang Bang.Only one other bloke said the same and that confused me as usual but with some thought as usual its on comparing Oranges with oranges, more Laverda orange references. For a start I weigh a lot more that everyone expect a very tall bloke and his bike has the later moved forward upper shock mounts, when that was done in the 70s in the off road world it was called layed down the shocks, it gives a more compliant ride as I think the forces move more freely on the racked angle. Must be the reason why Laverda did it plus it was a stronger arrangement mounted between the joining of frame rails.The only other bike similar to mine was ridden by a much lighter bloke, 75 to 80 kg compared to my 125kg.My issue with Icons is they have a huge bump stop that makes feeling the shock bottom hard to notice plus they do multi rate springs that firm up when getting to the end of travel. My little trick to identify whats happening is to push this bump stop down the shock shaft and see how much sag it has and what travel is being used.I couldn't do this on the ride as the soft panniers where in the way but I could jack up the preload and I did. Now preload usually has a minimal effect on spring rate, except with these multi rate springs it closes up the soft end of the spring and you lose compliance and that's exactly what happened.I did take some of the harsh big hits away but I then could feel ever tiny small hit, and also it jacked the rear a bit and made the bike a touch nervous, especially in the corrugated dirt bit we did. My bike has 20mm longer shock tops anyway, available from Icon as a spare part and added a few years back as I mainly do tight roads and that and the forks through the trees lightens the steering a lot and I like that.So this added preload at the rear plus Marty's replacement wheel with the std aspect rear tyre, 90 section as opposed to my usual 70 raised the rear just enough to add this nervousness in the loose gravel section. Still rideable and fine mostly but noticeable. Had me on tippy toes with the thickly padded touring dual seat plus air hawk. Anyway cut to the point, I am ordering the next hardest springs from Icon and I hope I can borrow a spring compressor from someone to swop them out and we will see if its helps with compliance on the more local shit roads and we have plenty of those.
Title: Re: Harsh Cer Forks.
Post by: motoddrob on November 14, 2018, 00:03
I'm not so sure about Ikon shocks these days given the choices available today. They're 70s technology.
Title: Re: Harsh Cer Forks.
Post by: Davo on November 14, 2018, 05:26
My Maxton shocks are great.
Title: Re: Harsh Cer Forks.
Post by: Vince on November 14, 2018, 06:30
Icon do an alloy body version for $600, the springs are $80 or so.
Title: Re: Harsh Cer Forks.
Post by: Tippie on November 14, 2018, 06:48
My Maxton shocks are great.+++++
With all your suspension work Vince, getting the correct weight springs is the absolute start point.
I used to change springs for two up touring (probably the two of us combined weighed your 125kg!), was brilliant, bike behaved like it had no passenger, totally different to the alternative of jacked up preload bottoming out all the time.
Title: Re: Harsh Cer Forks.
Post by: motoddrob on November 14, 2018, 06:52
Alloy body but with 70s technology?? or have they caught up?
I do have a set on the SFC
If I was to buy something today I'd probably look at
Gazi or YSS or cashed up Ohlins or Maxtons
Have to admit to being slightly cynical to Ikons.
Last dealings left an unpleasant taste!
Title: Re: Harsh Cer Forks.
Post by: Davo on November 14, 2018, 06:54
If you are keen on antique tech Vince I have a set of Konis you can have.
Title: Re: Harsh Cer Forks.
Post by: Brett on November 14, 2018, 07:58
3C still has its Ceriani's no issues here  :o

Title: Re: Harsh Cer Forks.
Post by: Davo on November 14, 2018, 08:08
3C still has its Ceriani's no issues here  :o

The original Cerianis were great shocks in their day, as were the Konis. Times have moved on. Hmmm, just thought about that, Laverda's were leading edge in their day as well...
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on November 14, 2018, 22:04
I've bitten the bullet and gone a pair of top-line Nitrons from DAM Laverda. Like Ohlins, they are far from cheap, but are the bees knees. I figured i won't be doing any more custom builds on this bike, so I finally want to finish what i started two or three decades ago right.

Very much looking fwd to reporting back on them ...
Title: Re: Harsh Cer Forks.
Post by: Vince on November 14, 2018, 23:52
Me too, how far off are you. I would love a topend pair of shocks, they if tuned right they just perform but most are at least $1500 and more.
Title: Re: Harsh Cer Forks.
Post by: Laverda SF on November 15, 2018, 00:18
All Cerriana Forks are HARSH  - Just gotta live with it !
Title: Re: Harsh Cer Forks.
Post by: Dellortoman on November 15, 2018, 00:49
When I put a pair of YSS shocks (replacing the Marzocchi Stradas) on the back of my MHR a few years ago, they made a big difference. The bike was a lot more comfortable to ride and the rear wheel actually stayed in contact with the road over bumps. I could get off the bike after an hour of riding without feeling like I'd been kicked in the arse a thousand times.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on November 15, 2018, 08:37
My 35mm Cerianis were a brilliant road fork for the era. Definitely not harsh if set up well and I think they even had bushes of some sort so stiction was not bad.
My build is a combo of waiting game getting work done externally and lack of time doing stuff myself. Been waiting nearly 4 weeks for a fairly simple machining job. Thought Iíd go local rather than travel far for trusted sources. Should have known better!
Unfortunately Vince any good stuff costs a lot, eg Carillos, but you get what you pay for. The only thing I can save on is labour.
Title: Re: Harsh Cer Forks.
Post by: Davo on November 16, 2018, 07:46
When I put a pair of YSS shocks (replacing the Marzocchi Stradas) on the back of my MHR a few years ago, they made a big difference. The bike was a lot more comfortable to ride and the rear wheel actually stayed in contact with the road over bumps. I could get off the bike after an hour of riding without feeling like I'd been kicked in the arse a thousand times.

Marzocchi Stradas. May as well put in a piece of solid steel. Had them on the Le Mans, even the Ikon replacements feel better.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on November 16, 2018, 12:20
Marzocchi Stradas. May as well put in a piece of solid steel. Had them on the Le Mans, even the Ikon replacements feel better.
Don't think I've ever heard a good word said about them either. The SF1 I worked on had them and they were shocking  ;D

When they're not leaking they're rupturing your spleen!
Title: Re: Harsh Cer Forks.
Post by: helicopterjim on November 16, 2018, 16:56
Marzocchi Stradas. May as well put in a piece of solid steel. Had them on the Le Mans, even the Ikon replacements feel better.

The concept of changing the spring rate hadn't made it to your part of the world?
Title: Re: Harsh Cer Forks.
Post by: Davo on November 17, 2018, 02:28
The concept of changing the spring rate hadn't made it to your part of the world?

I did exactly that. Threw the fuckers in the bin and put on Ikons. They were going in the bin anyway as it was found that the mounting ring on the left hand shock had around 1/3 of its circumference missing when the rear end was pulled off the bike so that the leaking rear crankshaft seal could be replaced. Just one of the many unpleasant surprises that came with the bike, now all fixed. All combined turned a reasonably priced purchase into an expensive exercise in repairing a death trap on wheels.
Title: Re: Harsh Cer Forks.
Post by: Vince on April 01, 2019, 03:17
Had a shocker of a ride on Sunday, we went up The Bells Line of Road and even the new 2 lane bits were unpleasant, cer forks on the 3c kicking off bumps and it one point shimmying across the road on multiple bumps. So today I went back to 15wt fork oil at 140mm.
My experiment at using 180mm didnt appear to work, dampers were covered with oil but not compliant at all at the higher level. With the new oil, it feels very compliant bouncing the bike. We will see next ride.
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 01, 2019, 04:30
Awwww I missed this thread...😗

The new tubes on my Ceriani have improved life.

Have been playing around with Sportsvalve rebound and I can dial out all the bounce but it's a bit harsh whichever way I go.

So as the springs seem short (theres a six inch spacer pipe to get to the top of the tube) and only two washers as preload adjustment (plus the bottom of the caps), I've added another couple just to see if it takes the spring into a working range that is better.


Title: Re: Harsh Cer Forks.
Post by: Vince on April 01, 2019, 04:47
Mine is the same except its got 5 washers to get to a good sag distance of 35ish mm. That's with a 9.5 spring. Me at 125kg as well. We can not compare valve adjustments obviously, mines a Race Tech and yours in that NZ one.
Title: Re: Harsh Cer Forks.
Post by: Vince on April 01, 2019, 05:00
BTW it was bloody windy in places where you suddenly appear on an open ridgeline, maybe that was some of the instability.
Title: Re: Harsh Cer Forks.
Post by: motoddrob on April 01, 2019, 05:35
After servicing the Marzos on the Motodd and drilling an extra hole in the Racetech valves, set the original silver spring at 3 turns, 150mm air gap and took out a 15mm preload spacer and using 15wt oil the front end has been transformed. Think I might even play with the WP rear shock now, probably room for improvement after using the same setting for 34 years!!!
I don't really fuck with settings, I just ride the fuckers 8)
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 01, 2019, 05:47
Mine is the same except its got 5 washers to get to a good sag distance of 35ish mm. That's with a 9.5 spring. Me at 125kg as well. We can not compare valve adjustments obviously, mines a Race Tech and yours in that NZ one.

When I get things right the bike is like it's on rails. I was a little short on sag for road at 25mm at front, back same 25mm and isn't using more than 70% of spring travel.
Title: Re: Harsh Cer Forks.
Post by: motoddrob on April 01, 2019, 06:48
When I get things right the bike is like it's on rails. I was a little short on sag for road at 25mm at front, back same 25mm and isn't using more than 70% of spring travel.

The beauty with the Motodd frame, it doesn't matter what the settings are they always ride like on rails ;D
If your ever in my neck of the woods you can try it out on my test track
Title: Re: Harsh Cer Forks.
Post by: cbertozz on April 01, 2019, 07:27
Hard to turn down!
Title: Re: Harsh Cer Forks.
Post by: cbertozz on May 15, 2019, 17:10
I've bitten the bullet and gone a pair of top-line Nitrons from DAM Laverda. Like Ohlins, they are far from cheap, but are the bees knees. I figured i won't be doing any more custom builds on this bike, so I finally want to finish what i started two or three decades ago right.

Very much looking fwd to reporting back on them ...

Have you had a chance to try them out yet? My first impressions were very good, although I feel that they may be a tiny bit under-sprung for me but time will tell.
Title: Re: Harsh Cer Forks.
Post by: Piranha Brother 2 on May 16, 2019, 09:34
Nor tried yet - bike is still some months off. Frame work in progress at the mo. Change of springs is no drama. With slow and fast rebound plus comp damping adjustability, there's a bit to get right.
Title: Re: Harsh Cer Forks.
Post by: cbertozz on May 21, 2019, 08:04
A couple of days at Collie should be a good shakedown.